The Exercise Myth

The Exercise Myfh

Gontenfs 1. The ExerciseMarketplace I 2. The Heart of the Matter 13 3. What StressTestsDon't Tell 24 4. The CaseagainstLongevity 44 5. The Inside Evidence 61 6. The Magic Runner 82 7. The Dangersof Exercise 97 8 A Better WaY 122 N OTES

136 IN D EX

145

Ihe Exercise

Morkefploce

them early in the noming on my way to work. I sccth€m Ey office windo{,s during the day. And in the evcning, are still hustling back and forth: women in stylish gear ing to exerciseclass;middl€-agedmenbuffng to andfrom C€ntralPark; peopleof every ageand &scription pantitrEand t catiig their way to today'sveNion of the healthylifestyle, I am a cardiologist,ase6gerto saveothers'livesasthey are to hold on to their o*n. And yet for all rny concemand their affort, exercisersare a6 likely as any to wiDd up anong my p&tients.Thos€exercis€rsI get to s€e,and pelhapsto help, are ody a few of the tensof miUionsin the United Stateswho lrow run o! jog regularly, and the merest ftaction of those many millions more in this country and a.ound the world who have trlen up the bannerof vigorousexercisein general.They are ihe reprcsentstivesof all thosewho havc bought the mistaken idea that strenuouscffort promoteshealthalrd longevity.They

THE EXERCI SE M ARKETPLACE

T H E EX ER C IS E MY TH

inq. We've come a long way, but why? Runners iun and ex' criisers exerci"ebecauseso many peoPlehave told them it's good for them physicaily.emolionally. socially and even spiF itually.The dislinctionsbetw€envariousbenefiIsare ratherblurred to judge b' lhe books and magazineslhal promote exercise Sen a smashingsuccesson the newsstandsthese days, is de' scribed by its editor as a magazioe of "physical and emotional well-being." The titles of other oew entries into tlle field-Nelt Boily, Ame ca Health, Shape, Fit, Sp/itr8-promise a blend of {adrant skin, lithe figure, athletic prowessand excellent health whetherdevotedto motherhoodor fashTraditionalmagazines, ion, have dramatically altered their format and tinrst to reflect

exerci:e seekan unaltainablrgoal The) dre the ticlim\ ot lhe m)4h. No one knows exactlyhow many individualsexercisehard goodand often in the belief that they are doing themselves \tork oul Althoug,hlhere are probab\ millionsof beliererswho classes in dance club:' handballcourls.al tennis in gy.s. "n visible the most an; othet meeting grounds, runners are today of those who inco:rporate vigorous and often punishing exercise least' into their everydaylives You can get an imPression'at clty pavement oi the pound of how many joggers doggedly just Iookrng by streetsor troi the shouldersof suburbanrcads arcund you during the popular early-moming and afier-work trours.iheir numberhasbeengue\sedIo be l0 million who More reliablenumbersexislfor "real runners-lho\e 300 about now are nrn marathonsor enter lesserrac€s There Lebow' Fred oruanizedmarathonsnrn yearlyaroundthe world lo "marorisidentof the New \ ork RoadRunnersClub re[ers racing such organized \pread of athon fever" ;n describingthe anentranlsi regislered The Boslon Maralhon hasabout 8.000 them call other 8,000unregisteredrunneN-the rcgiste{ed racen Mini-Mara"bandits"-usually join the race. The last L'Eggs about 6'500 registered City, York thon, a 6.4-mileracein New popular increasingly women from 34 statesand 8 countries The lhe and Montreal Marathon now ha\ about 10.000entrants all' now New York Marathon, Pelhaps the most famous race of guess that to have would One attracts about 17,000registrants joggers or "mere" there are hundreds-maybe thousands-of at b€ must there novic€ runners to every registered racer' And exercise least as many people who stnve for their weekly doseof in other ways. In formir days, the healthiest form of exercise was thought could tobe a daily "co;$itutional"-a modestlybriskwalk that pantbe accomplishedwithout special gear and certainly without

the new €mphasis on exercise. Social pressure to Participate in the movement is quite real' You're as likely to hear mention of "aercbics" and "cardiovascular fitness" in cocktaifparty conversatron as you are lo hear about the latest theatrical hit, new restaumnt or fashion news.And you're expectedto respond with the right knowledge, jargon and enthusiasm. Knowledgeand jargon aren't hard to come by. Bookstorc shelvesare 6lled \trth exercisebook\. trealiseson ho* to run and when to run, on strengtheningyour body, on cbangingit and making it better. The enthusiasm is catching Jone Fondo's york Times best' Workout Book was n\mber one on the New seller list for 51 weeks-in some sPot on the list for 92 weeksand James Fixx's best-selling bookl on running sold nearly 1 million copies in hardcover alone lts authol' who said he could "show you how to become healthier and happier than you ever imaginedyou could be,"' becamehiglly visible in television : :

commercials, Strong business and career pressures are often exerted to . " The notes de on pages 13G143

T H E E XE R C IS E MY TH

make people conform to the dogma of the ex€rcisebelievers' may compelolherqise Subtle- and nol.so-subtle-influence\ physical_activityproin unwilling individuals to participate gams. In 1980,over 3,000 businesseswere providing health/ fitne"" prog.u-s for e-ployees. Somecorporationshave made laree financial investments in building their own exercise facif iries for the use of all lherr personnel.Other companiespay considerablesums of money to outside exercisefacilities for their executives,and individual participationin the Programs may be periodicallyrevievred-RunnercHandbookrcportedthat in one maior corporation, employeeswho don't exerciseare gently admonishedby their colleagues.No wonder; $5 billion is spent yearly on employee-fitness programs'2 and no business likes to seeits investmentswasted. The CorporaleChallengeSerieshas become.excepl for the New York Marathon, the largestrac€ organizedby the New York Road RunnersClub. lt receivesa lot of media attention' andcompetition,while ftiendly, is intense.The latestCoryorat€ Challengerace attracted8,000runners.As describedby Deborah Greene.rac€ director of the 1980Manufactulen Hanover Corporate Challenge, in New Yotk Run/ti g News,"after a hard day at the office, tired corpolate workers, ftom office boys to for a presidents, wended their way toward Central Park parading the streets to run, competitiverace.They camedressed in shorts, running shoes,and singletsemblazonedwith the names of their companies.They . . huddled under the signsor banners of theil corPorateteams."r Wlether facilities and proglams for exerciseand competition are foslered by lrue bul misplacedbenevolentconcem on the part of corporatemanagementor by the unprovenexpectatron and hope of greater employee productivity, the fact is that the manageror executivewho doesn't see these corporate commitments as an unspoken corporate philosophy or command

THE EXERCI SE M ARKETPLACE

world' msy be tisking career advancement Within one's business $;ithin one'sneighborhood'being "into" exerciseuddeniably conveysa c€rtarnstatus Te'levision has had an important iniuence on the fitness pubohenomenon.The glodficationof winnen and the intense iicity surroundingwhat are largely media events-the runner has been called the "darling of the media"-allow even fte regular nelwork television amateur to feel special '!,Vhereas blazealthe trail by increasing coverage of the professional and trained athlete, cable television focusesheavily on the unhained amateur, that person at home who could be you The Cable Heahh Ner\\ork, for example is a relalivel) new lwenry-[outhour cable televisionchanneldealingonly with health and 6tness.A wide rangeof programsis broadcast wilh lhe healiesl emDhasis _Th" on exercise. that exercise is bene6cial-reflected ill th€ "onr"o.u. social. career and media plessures to exercise, and the coupling of fitness to health, beauty' sexual, social and businesssuccessis both the product of, and the impetus for' a variety of exand unfounded claims about what exercisecan do fo' travagant -Manv promise mrdical help. A highly successfulexercise vou. **.. in i'1." York offers a syslematicprogramdesignedlo strengthenyour heart . . . and help reducecoronaly nsk factors. i . ." A professional dancer offers a cou6e in aerobicsthat " and have you will "strengthen your cardiovascular system "thoroughly enjoy your retum to good health and a good ligure." A;a;ionwide network of rehabilitationcentersfor cardiac patients promotes "safe, supervised, telemetry-momtored exircise therapy. . ." thtough which "you'll find a new way ot life . . . an atmosphereof hoPe,not heartbreak" Even a manufacturer of com oil oflers an "information-packed booklet" in ' which "different tlpes of exercisesare evaluated for fitness and caraliovascularhealth." And a dentist suggests that you "Jog

T H E E XE R C ISE MY TH

over" to his office for special"dentistry for the runner." Promisesof medicalhelp often tend to shadeinto promises of spiritual renewal. One exercisecenter coins a new term, "biofitness," and offers "a tailormade program, basedon individual needs,to integrate the mind and body in a get-wellget-bettergoal." Perhapsthe exaggerationof benefitsand blurring of claims are best summedup in the advertisementof a large sportinggoodsstore, which promisesthat its indoor jogging treadmill focters"CardiovascularHealth, AerobicFitness, FacilitatesSleep, Better Balance,Muscle Strength,Fe€ling of Euphoria, Better Heallh.lncrea\edStamina.weight Conrrol.' No wond€r people are willing to pay for such a panacea. And pay they do. On the basisof amazingclaims,the public is spendingenormoussumsofmoney for exerciseclothing,equipment and programs,and exercisehasbecomevery big business, On Wall Street, it would be called a "growth industry." Sales of jogging shoes,for example,have morc than doubled in the last five years,althoughsome may buy them more for comfort or stylethan for running. One out of every three pairsof shoes sold in the Uniled Statosis sneakeis.The Nike Companyalone sold about 13 million running shoesin 1983; and their total sales,now includingother apparelas well as shoes,are in the hundredsof millions of dollars. The sheernumber of different runningshoesis astounding.Afew yealsago,a leadingrunners' magazinelisted about a dozen brands.The latest availablereport lists over one hundred. The number of models must be staggering. The National Sporting Goods Associationestimated 1982 salesto individuals(not countingany institutionalsal€s)of athletic equipment,includingbarbells,treadmills,tmmpolines,exercisebicycles,rowing machinesand jump ropes,to be $499.4 million. Individualsbousht 42.2 million Dairsof exercrseshorts

THE EXERCI SE M ARKETPLACE

on \weat\hirl\' rnd lor ill?4 million they spent$212mrllion ol B Doyle Llirecror iltr rlttion on qarm-up\uits Thomas figures these calls ,"t"ut"h for the association' iii ,rtution "na percentlower than ac_ .rrn*"ruutin",and e"timat€sthey are 25 trrl salesfiqures lo heaul) \lalus tn teeo"inswith the couplingol exercise ol clothrnge\ercisenis high la'hion nnJ.".."i., irt. business i' lockeFroomchic ha\ beencoinedand Th. t.'. ;;;;;. mag^zrne a ne\t riruallv the name of lhe lashion seclion o{ hals visor5\un_ shirts short\' socks W"rt-'to *i,., running eucall promotedvia an inseniou\ly fi,'*r. it*aOr"a'. ari ccssfulamalgamof fashion and hlness just as trendy and slavish Runnersanrl other exercise$are Of cou$e, much of the fashionem' tn fJion u. unyon" "l.e numberofnew plodohasishasbeen directedto women' and a demand-Sincethe the to capitalizeon lr"o t ut. t""n "t"ut"a greatly'manufacturers nurnU".of *o-"n utttt"teshasincreased than a dozen "spo(s bras" in the past h"u" introau".a -ot" bounce" and "joggers' nipples" are now t"* y.u.r. "fogg.t"' your sport"'one brand *.-i" ,".-" O*f"tce. "Whatever "ii.,ft"r.f u i.u. . . ." They offer the racquetbra and the "fui.r, bra, as well as the running bra ,J"l*o-un """."i"t devotionto phys_ Most believersin exercisedeny that their promolron'\ocra' by adverlising icalaflivil!i: great\ influenced The' claim lo be immunelo \ucn n. career'consid.,ariont on "selling" exercrse blandishmentsalespitethe money spent beauty and success' with throush the allute of its association

getting viJin .i."*u,ion. .uggestotherwiseAnd' anyway' does probabl! rrack ,* .ou*, o-ion the runnrng r"Linf, and ""so.iatuen.nt' iuslasexercise amongexecutives iuie som. henefitsUkima!ely' iurine"speopleprobabt)doesoflercareer reasonlor their ,r'.""i i-.l.r.i" onei a 'o" hard-nosed erercise punishing i.""oiion.I'.v *r,.'" thatvigolouseten

TH F EXERCI S E

MYTH

leadsto beiter health and longer life. They bclicve,specifically, that excrcisepromotes cirdiovascular heallh and protects against heaft attack, the leadingcauseof dealh in this country and in other industrializedsocietics. The idea of immunity from cardiovasculardiseaseby virtue of vigorousexercisehasbccn lhefourdation uponwhich interest and participationin exercisehave 8rown. Achicving a longer life and a healthierone through exerciseis ihe singleconstant rhr
THE E\ ERCI \ E

M ARKETPLACE

entitled "CorI{esearchCouncjl,London Hospital ln an article PhysicalActivity of Work'''published ,,""r" ff.^n Oi..^"" ""d Morris and his i,' lq'si i" tr'. s.erl.rl tedical journal Ldnc?t' heaYl of comparedthe amountand selerity coronary colleasues They ,ri."u.i in f-onaon bus drivers and in bus conductorsmore coronary observedthat the morc sedentarydrivers had concluded They conriuctors,i;r*"t ,ft* alid the more active heart drs' coronary rhat physicalactivity offers protectionfrom of this ihe.e *os n., gr.at public reaction1rrthe appearance it had considerable t"cttni.ut pupc. in u scienti{icjournal but in ir a neq glrmmel sn$ on rhemedicrlpfoles\ron\^hich rmoacr Torhi'dal Motrist .'iion. r*tft.p'"'.nilonotheartdi'(rt r lan'imJrk irs conclu\ion\$cll Inosn lo rrudt is considercd '- .eii.i,rr" publication of Morris's original paper' a stcadv health benefitsol rt.*rn ot orti.t". conceming thc possible ke(Fing ,"i"i,t heganto appealin meJlcaliournals lc\el Vern$hile' "itr""r l"ir.,,. ,. u,opi. "i*.aical conc(rnat a high use' and it lulled common u ai"*o*i. test was coming into the condition anlto'." lnto t"fi"ulng,ftey couldlherebydiagnose exercisewas ni u ootl.ot. heart, and could even tell whether StepTesl' named ,ut io, tttut p"."on fnls wasthe MastcrTwo

York Citv' i".-ri. a"*rirp-, Dr. ArthurM Master'of New his reportcd late' ihe testin about1925and *i"'iri-a*"d

resultsin leadingmedicnljournals' was that abnormal_ The idea underlyingthis lirst stresstesr rest could becomc ar apparent ities of the heart that were not ln other words' stress conditions of physicat .riA.., ".a.. cardiacrctbnormal otvsi.ot ,t.es" exercise-could proloke activity' physic'l loin..s. sinc. ttre trca.t works harder duting it be u""O to tring out heart trouble Conversely .'ffort s patient thc then "oofa provoke abnormalities' ihysical stressrlid not

T H E EX ER C IS E MY TII

heartcouldbe consid€rednormal.The logicalcorollarywasthat a normal performanceon the stresstest meant that physical As time went on, refinementsin exercisestresstestingwere made. In addition to the simple stepsusedin the MasterTwo_ Step Test, treadmillsand exercisebicycleswere developed.A steadypromotional effort began to be directed at physicians. Many new companiesmanufactuing exercisetcstlngand monitoring devicessprangup. Soon, the age of computer-assisted stresstestingarrived.The newerdeviccs and computer-direct€d and complexcomparedwith theoriginal arehighlysophisticated Two-Stepdevice,and cofiveya muchgreatersenseof diagnostic precisionand accuracy.Manufacturing and marketing efforts today are strongerthan ever, lf the scienceand technologyof modern-daystresstesting are somewhatconfusing,even 1(]many physicians,the financial incentivesare clearer.Sincestresstestingis a complicatedand potentiallyrisky procedure,and doestakc time, feesare high An exercisestresstest in New York City, fbr example,may easilycost between$150 and $250. To many physicians,fees from stresstesting in its various forms representa signitjcant percentageof their total income. The marketingeffo s of companiesselling exercisetesting equipment to physiciansalmost alwayspromincntlyfeatute the €conomicrewardsto be gained Everysaleseffort evermadeto me by acompanysellingexercise equipment has emphasizedhow quickly I can earn back the cost.The companyeven providesan analysisshowiry iust how few testsper month are neededto break even, and then how many to earn multiples of th€ purchaseprice. And sinc€thirdparty payers-Blue Shield and other health insuranceploviders-cover muchofthe costofthe tests,financialconsiderations rarely dissuadepatientsfrom havingthe testsdone More entrepreneurialindividuals,recognizingthat increased

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THE EXERCI SE M AR( ETPLACE

volume means increasedrevenues,have establishedexercise Igstingcenters.Peoplecome on the own or are referred by or exerciseclinicsfor stresstesting These exercrse Dhvsicians i"silng centen are often owned outright by physicians Alteratively, physiciansmay have equity positions,usually in exchangefor servingas "consultants"or "advisers ' Siresstesting is actualtyonly a small Part of the financial rrwardfrom theseexerci\ecenter(. Suneniscd exelci'eptogramsrepresenta much greater linancial retum More and more, iardiac patientsale being advisedto participatein regular excrciseprograms.Since some 350,000people surviveheart attackseich vcar and there are altogetherseveralmillion cardiac oatientsin the United States,the potential "pool" of subjects is very large. Most exercisetesting cenlersalso run supervlseo cxerciseprograms;the levenue potential is obvious More than 20 "cardiac rehabilitation clinics" oPenedon Inng lslanal.New York. alone in the last few years As the field of exercisetestingand supervisedexercis€progmmsgetscrowoeo and compet,lionrs lell. one wa) lo help in\ure a \uccesslul operario;ha\ been Io divideownershinamongseveralphlsilhe program cians.who lhen ha!e an Incenli\eto recommend to their patients.One suchcenteradmits' accordingto the Nelt york tmes,lhal 85 percenlol lhe programs patienlscome rromshareholder PhYsicians Of course, not every physicianwho recommends€xercrse doesit out of venality or solely for profit. Doctorc themselves padcipate in vigorous wo*outs and demandinggames At many medicatmeetingsthere are running groups who are accolded specialstatus. One major pharmaceuticalcompany sponsors min;marathonsfor physiciansand tleir spousesat varousmedical conventions,Th€seracesfeaturetrophiesand awards'and, jt as a companyspokesmanpuns, "are just fof the health of " Doctors.de.piretheirmedicaltraining.are con\umersiustlike

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T H E EX ER CIS E

everyoneelse, subjectto the sameexerciseballyhoo and hype as the rest of the population. So, everythinghascometogether'The enticementofprolit' the seductionsoffashion and status,and tlle legitimacyof medicine all supportthis amazingexercis€Phenomenon.So huge a bandwagon,fueledby the profit motive and weightedby a population woded about its healtl and believingit has found the answer.hasa ternble momentum.The sober truth may nol be enoughto stop it, but the truth shouldbe stated: You may enjoy exercise;it may be helpful socially;it may make you look and feel better' But all the rest is m)'th Exercise will not make you healthy lt will not make you live lonser. Fitnessand health are not the sam€thing.

TheHeorf

of fhe Moffer Most of us respondeasily to the common greeting"How are vou?" becausewe have an intuitive sensethat how we feel is' in fact, how we are. lf we feel well' we answerthat we're tine' nell and ,f qe don t feel well. \re may rePl) lhat $e ale not hoqerer' we are how Thisinluilivemergingof how we feeland often incofiect. is quit€ _Even in a strictly medical setting, people may mistakenly I equatehow they feel with th€ir actual state of health When infbr' specific asi a patient "How do you feel?," I am seeking mation about symptoms.When patients reply, as they some_ timeshalf-jokinglydo, "You tell me; you're the doctor"' I say' " "You tell me how you feel; I'll tell you how you are The not necfeel is we Doint-and it is a crucial one-is that how health' issarily how we are. How you are is a stat€mentofyour ab_ anal has to do with the presence or absenceof disease or ion :ummat complex you is a feel How normalbodyconditions

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T H E EX ER C IS E MY TH

of physical,mental and emotional factors that is often independentof your actualstate of health. With regard to cardiovascularhealth, t]le divergenc€betweenhow we feel and how we are may be especiallystriking. And the implicationsof this discrepancybetweenfeeling and actualitycan be serious.How we feel is largely dep€ndenton what we can physicallydo-what is called "fitn€ss"-but how we are may have little or nothing to do with this. Fihess and health are distinct and independentof one another. Fitnessis defined by your ability to do physicalactivity or to pertbrm physicalwork. It is a measureof your "functional capacity."It doesn'treflectthe presenceor absenceof disease, and impliesnothing about the actualhealth of your arteriesor your heart. Cardiovascularhealth refe^ to the absenceof diseaseof the heart and blood vessels,not to the ability of an individualto do a certainamountofphysicalwork. Your overall cardiachealth is determinedby rhe condition of variousheart structures,including the hearr muscle,the valves,the special cardiactissuesthat carty electricalimpulsesand rhe coionary artedes.Thc health of coronary arterieshas been claimed to be relatedlo exercise. Coronaryarteriesare those that carry oxygenatedblood to the heart muscle. Healthy arteries are smooth-walledand of sufficientdiameterinsidefor blood to flow freely throughthern_ In corcnary artery disease,or coronary hea disease,the arteries that carry blood to the heart muscle are narrowedand obstructedby deposits.calledplaques,ofcholesteroland other tatty substances. The heart musclecells. like all other cells in the body, require oxygen to do their work. The heart do€snt get its oxygenfrom tbe blood insideit but from the network of coronaryarteriesthat travel over and throughthe heart muscle. The pathologicprocesswhereby rhe arlery walls fill up wirh fatty substances and tlereby narrow the channelthroughwhich

THE HEART O F THE M ATTER

lt is lhe major ahnor hh'odllo\ s js called alheroscletosi\" ot rhe arteriet r"iin in *rtu, i, .otrnonl) called hdrdening tissuestnvels in the sincJaff tle o*ygencardedto the body "f 8ow decreasesowgen hlood, anything thal decrease\blood or narrowed by blocked ,uoo|y. ri4t.n coronary arterie\ are not enough blood and thetefore nor enough ,,ii-i..f.ro"i., oxveenreachheafi musclec€lls 'io.ooary no heort diseasecan be "sile t" and produce itself in severalways'ofwhich the o. it.un -,in"i of angina ""roto.., -"nifest u.", ttt" .hest pain and breathlessness this and-and "orn.oo **l"r event of a heart attack tft" about are "*" These "".i".it. l,* t" it" fitt, ".y.ptom"-sudden death diseasemakes ery a way coionary u.irt. nnt "o..oo the pathoccurs' of these "-oiinlro iti'or.'..o". foo*n. ey the time ofle going on for been .rn!i. o.o".". nr utn.to.clerosishasprobably somellme. in the breast" ,q.nsinapectori" tite.ally means"strangling chestpain that ho." ino.a" u..otut"ty aescribethe constricting blood inadequate when ihere is a rempolarilv ;;;.;;""" lypical thi\ palrenthas iuJorr ro t'.arr musclecetls Nor every feel lesscrushing instead may person .il,Ioion, no*"u.. The well as bleathlessas pressure' o'ain'.u sensutionot u,rrningor attacK' angina an iess. weakness,faintnessor fatigue During needs' lhe heart o*yg"n supply are lesstlan *i"n utooa and the ""a tf the blood i"".i ."*r" *1. ^i" ,"mpoiarilv injured s need for ."oo,t are increased or lhe heart mu'cle inlun lrom recover ""raa" iilJa r",l .*vg.n a."t.ars rhenrhecell\ the symplomsgo away compleleL) and in[arcur,o.*,-tnownmedicall!as a myocardial lt."n m sclecells when tion.l' representsact.al deathof someheart v'rtudll) un.ry i..o nurro\tedthatlhe bloodsupplyi\ severelyoxlgen"io-nulv cur off to an areaof lhe hean muscle the injured and die' a"pti""a l*u musclecells are permanently

15

T H E EX ER C IS E MY TH

Angina pecrorisand heart attacksare really pan of the same problem,but in anginathe blood and the oxygensupplyare not so inadequaterclativ€ to the heart muscle'sneedsas they are in a heart attack. Most initial hea attacksare nor fatal. but if they are extensiveenoughor causesevereirregularitiesof the heart rhythm, they can causedeath. Subsequentheart attacks are often more dangerousbecausethe new damageis superimposedon the old. Suddencardiac death, the third common manifestationof coronaryheart diseas€,is usuallydue ro an arrhythmia,or irregularityof the heartb€at.There are many kinds ofinnocuous arrhythmias,and many normal peopl€ have them. Only one type of arh]'thmia is usually quickly fatal. It almost always occursin peoplewith someseriousform of heart disease,most usuallycoronarya ery disease. Thesethree expressions of coronaryartery disease-angina pectoris, hea attack and sudden cardiac death-are by no meansmutually exclusive.Angina pectoris,for example,often precedesa heart attack, although it may first occur following one. Suddencardiacdeath may happenwithout warning,but it also often follows a heart attack. And all theseer?ressionsor none of them-may occurin anypatient with coronaryheart disease.But theseindicarionsofthe underlyingaonditionofthe heart and its arterieshav€ no relation to fitness.peopl€ with coronary heart diseaseand no symptoms,those with angina pectorisand heart attacksand thosewho will experi€ncesudden cardiacdeath may all be in fine shapeas far as their ability to exert themselvesis concerned,Furthermore,almost no matter what their level of fitness,they may all enhancetheir functional capacityby exercise,yet the condition of their heart remains

THE HEART O F THE M ATl ER

The fact that health and fitnessare distinct,that peoplewith Severe,even imminently fatal coronary heart diseasecan be

vcry fit and that individualswith coronarydrseasecan enhanc€ their functionalcapacityby exercisewithout therebyimproving their h€alth may be difficult to accept The fact becomesmore however,with an understandingof what fitnessis, hcceptable, snd what the heart has to do with it. The amount of physicalwork you can do-your fitnessultimatelydependson the amount of orygen that your body tissuesreceiveand can use. Functionalcapacity'in fact, is defined by physiologists in terms of oxygen utilization or oxygen consumption.The more oxygen your body can use' the mole activity you can do; and t]le nore physicalwork you actually do, the more oxygenyour bodyconsumes.Your ultimatefitness orfunctionalcapacity,then, is measuredby the greateslamounl of oxygen your body can use when you are performing at peak effo . Since all of the oxygen your body tissues receive is carried in your bloodstream,and since the blood is pumped around your body by your heart, it seemsintuitively logical that your functional capacity must depend primarily upon your heart An increasein your capacityfor physicalwork seemsto rmply an increasein the performance of your heart As a logical cons€ouenceof a Dresumed€nhanc€mentof your heart's performof a "stlonger heart"' "healther heart" and ance.the not_ions cerlainbthosenolions ''berterhearl seememinenilysensrble: accepted. uncritically have become YouI heart and cardiovascularsystem, however' are nol alwa's logical.What seemssensibleand app€an reasontbleis not necessarilyso. The fact of t]le matter is that much of what constitutes an improYement in your ability to perform physical directly related to your heart Althougl cardiac work is ''ol occur as functional capacityincreases,they are not changesdo inherenlly "better" or "healthier." Sincethe amounlol oxygenlour bod! can usedelermine\

l6

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T H E EX E R CIS F MY TH

THE HEART O F THE M ATTER

your capacityfor physicalwork, your body.sfitnessis limited by the amountof oxygenavailableto it. This, in turn. deDends uponlhe amountot orlgen In lhe air !ou brearhe,an,lon the conditionof your lungs and your blood. Oxygenis transferreal ftom the air to your bloodstreaminsideyour lungs;diseasesof the lungs or abnormalitiesin rhe blood itself can inhibit this normal transferof oxygenfrom the air into your body. Assumingthe air you breathehasnormal amounrsofoxvsen and)ou haveno unusualIungor bloodcondirron rharrnr.riere. with oxygenenteringyofi bloodstream,rhe amounrof oxygen your body has available ro ir then dependsupon how mucb blood your heart pumps to your c€lls.your heart can increase the amountof blood it pumps around your body by incrcasing the "heart rate"-the numberof heartbearsDerminute-or bv increasing \ahalis calledrhe strokevolume rhe amounLol blood pump€d with €ach heartbeat. Assumjng th€ heart is pumpingplenty of blood around your body, how much oxygen can be used ultimately dependson the body cells. your body cellscan increasethe amount of oxygenthey useby extracting moreofthe availableoxygenftom the blood that comesro them. Wheneveryou exerciseor perform physicalwork,your body normally respondsin a nurnber of different ways. The most important of thesechanges,leadingto increasedoxygenavail, ability to the body'scellsin rcsponseto exertion.are increases in yourh€art rate andstrokevolume.Theseincreasesare mainlv dueto nervesigna15 thar hrainsendslo )our heana, more oxygenis needed.The combined effecrol the heart chans€sis 'our to pump morebloodand therebymakemoreurygenarailahle to the cellsof your body. Bur, additionally,removalof oxygen tiom the bloodstreamby your body,s musclecells increases. sinc€cells that produce and r€leaseen€rgy at high rates, tike workingmusclecells,extracta largeportion ofth€ oxygenfrom the blood. All three effects-rhe increasesin heart rate. stroke

volume and oxygen €xtraction-combine to allow you to do

18

lf you exerciseregularly at a certain intensity and for a rcrtain period of time, you can achievewhat has been called thc "training effect." The telm ref€rsto a seri€sof physiologic changesthat occut in the body as a result of doing regular "nerobic" exercise.(Aerobic really just means"oryg€n'usingi" lnd thereforeall human activity is aerobic;appliedto exercise, however,aerobicrefers specificallyto activity in which the amount of oxygenused by the body increasesdirectly and predictably with the amount of physical exertion-) These physiologicchanges of the training effect include: slower resting heart rate wh€n you'reinactive;slowerheartrate andlowerblood pressurewhen al )oul pedkle!el: faslerrelurnlo yournormal you re e)\erting restingheart rate after you've finishedexercising. Somehowthe notion mistakenlyarosethat thesephysiologic changesof the training effect are automatically"healthi€r" or "better." But there's no evidencethat a slower resting heart rate is healthier than a heart rate somewhatfaster, or that a quicker return to restingheart rate after exerciseis inherently beneficial.Nobody has shown any biological advantageto a slowerheartbeat.I have patientsin their eightiesand nineties who have somewhatmpid hea beatsand have had them since their childhoods.Ifyou w€re born with a finite numberofheartbeatsfor your lifetime, then a slower heart rate would be desirable,sinc€you would live longer before usingup your allotment. But there is no suchallotted numberof heartbeatsfor anybody Slower heart rate and lower blood pressur€at physical exe ion levelsless than your maximum could possiblybe advantageous.This would be so if you had a heart condition like anginapectoris,and physicalactivity provoked chestPainsor becausetoo little oxygen was suppliedto your breathlessness heart musclewhen you exerted yourself. With a slower heart

19

T H E E XE R C ISE MY TH

rate and lower blood pressur€,your heart musclewould require lessorygen (heart rate and blood pressurelargely determine how much oxygenyol]r heart muscleneeds).you would, therefore, be less likely to hav€ angina attackswhen you exerted yourself,sincepain and bteathlessness occur when the oxygen needsof the hean muscleexceedthe oxygensupply.By lowedng th€ heart rate and blood pressure,you reducethe needof your heaft musclefor oxygen,and bring that need into balancewith the oxygensupply.But, think of the paradox:in order to achieve slower heaatrate and lower blood pressure, you have to exercise rcgularly and raise yow heart rate and blood pr€ssurewhile doing it! lf a reductionin hean rale and blood pressureis necessary for you becauseof a heart condition or other rcason.rnere are meansother than exerciseto achievethes€ ends, Relatively simple medicationsare available,and, in fact, are safely and regularlyused by millions of people in the United Statesand aroundthe world. Thesemedicationsnot only lower the heart rate and the blood pessurebut also are ,.cardioprotective,,, that is, they help to preventheart attacks.This protectiveeffect has been prcved in patients who have already had one heart attack, and many cardiologistsbelievethe protectionmay extend to thosewho havenot, althoughno specificstudieson this point have been made. So, if a slower heart rate and lower blood pressuieare necessarygoalsbecauseof heart disease,it seemsimpludenl to undenake a vigorousexerciseprogramto achi€vethem. Of course,one can arguethat medicationshave side eff€cts and that it is preferableto achievethingsin a ,,natural" wayas if pushingyour body to near exhaustinglimits and purcuing somearbitraryheart-rategoal are ,.natural.,,Ifs true that med_ ications have side effects. Every medicin€ may hav€ some side effect in some parients.What is ignored are the possibleside

20

THE HEART O F TI {E M ATTER

lffects of exercise-side effects that may be mor€ severe and more dangerousthan tlose due to medications. disease, In normal individuals,thosewithout cardiovascular one evidentchangeoccu$ to the heart with prolongedphysical training.It is the so-calledathlete'sheart, where the heart enlrrges, at times dramatically. It pumps more blood witl each hcartbeatand there are microscopicchangesof unknown significancewithin the hea musclecells.Whether th€seare biologically beneficialchangesis entirely unclear; many of the changesresemblethose seenin hea disease.Enlargementof the heart,for example,is often a serioussignof a diseasedheart compensatingfor difficulties in pumping blood-but in an athlete it is said to be a beneficialadaptationto increasedperformance.Athletes frequentlyhave abnormalelectrocaldiograms, manifesting changes that in nonathletes would be considered unmistakable signs of disease.The advocatesof vigorous exercisetraining dismisstheseas "nolmal" adaptationsl am not at 6ll sure. Although the athlete's heart may function superiorly, it may not be a healthierheart. As for increasing maximum orygen consumPtion when you are exercisingat your peak, there is certainlynothing intrinsically healtlier about that. If you're an athletewhosesport rq quiresprolongedexertion and endurance,then it is necessary. If your lifestyle rcquires the ability to perform more physical work, then you must exerciseto achievethat caPacity l have no quanel with the fact that exercise training is the only way to indeaseyour physicalcapacityfor work. What I do seriously questionis tbe idea that it is healthier. Fitnessis measuredphysiologicallyby oxygenconsumption, and your body may be efficientin its use of oxygen,so it uses Iess for a given amount of work performed. But this doesn't meanaJhingto your heart, in sicknessor in health.Peoplewjth even severc coronary heart disease can be "trained" with ex-

21

T H E EX ER C IS E MY TH

ercise,but it doesn'talter the fact or severityof their coronary artery disease. Most of the improvementin functional capacitydue to exerciseis not even direcdy relat€d to the heart. It is due ro an effect on the periph€ral musclecells whereby they more efficiently extracl and use oxygen from the blood. Dr. ceorqe Sheehan. the guru of running.har said...you mighrsu.pecr from the emphasison cardiopulmonaryfitnessthar the maior effectof trainingis on the heartandlungs.cuessagain.Exercise doesnothing for the lungs; that has been amply proved. . . . Nor doesit €speciallybenefit your heart. Running, no matter what you have been told, primadly trains and conditionsthe musIn peoplewith heartdiseaseespecially,viftually all improved ntnessis due to changes in the abrlit' ot Lheperipheral muscle cellsto extractand useoxygenfrom the bloodstream.The exact m€chanismby which musclecells becomemore efficientin removrngoxygen and using it to generateand releaseenergyis unknown, but it is not due to any measurablechangein the health or the function of the heart. Columbia Universitv car,liologrsr Dr. Jonarhan Moldo!erdeniesthere15sucha rhineas ''cardrovascular ntness. because fitnessis relaledro periohlral changes,, If physical fitnessinsured health in general, then only an accidentcould bring down fit individuals.Ce ainly if cardiota\cularhealthwereeithera productor a precondition ot phlsical training, then fit peoplewouldn't die of heart disease_ The fact is that not only do exerciserssufferthe usualills that Dlasue us all. bur rhe leadingcauseo[ exercise-related deartrs in welltrainedpeopleis coronaryheart disease. You can, of course, be fii and healthy. yet you can be physicallyfit and fatally ill with coronaryheart disease,iust as you can be wonderfully healrhy but quite unfit in terms of ex-

22

THE HEART O F THE M ATTER

crcisecapacity.Finally, you can be unfit and unhealthyas well. It is this last categorythat posesthe greatestproblem both to the medicalprofessionand to would-beexercisers.Th€ outwill put quite a of-shapeperson who also has atherosclerosis pressed in the processof for oxygen strain on a heart aheady becoming6t. Yetpeople may undertakeexercisewithout knowing what condition their heart is in, and doctorsmay pr€scribe exerciseto those they know to have heart disease.Sincethere is no clear or direct relationshipbetweencafdiac health and aerobicfitness.a doctorwould like toknow6ot howfitaperson is and what condition his hean is in before assuringhim that he can safelyjog two miles a day. Therefore, physicianshave soughtfor waysto diagnos€healt diseasewhen it is Present,to excludeit when it is abs€nt,and to assessfunctional capacity. The basictool in current use is the exercisestlesstest

23

WHAT STRESSTESTS DO N'T TELL

Whof SfressTesfs

DontTell

Each year tens of thousandsof newly convertedbelieversare tumed loose by physiciansto join the millions of alreadyconfirmed exerciseenthusiastswho pound the str€ets,fill the parks and line the roadwaysof our citics and countryside.For thousandsmore, exerciseis formally prescribedand ,.dosages"es, tablishedaspart of a treatment regimcn in the hop€sof preventing atherosclerosis, reducingsymptomsof anginapectofs or fore stalling a heart attack. The approval and rhe prescriptionof exercis€rest largely on the foundation of a srr€ssrcst. The basicconceptunderlyingstresstestingis that someabnormalitiesof the heart that are not apparenrwhen you are at rest may be.ome evident during physicalwork. Your heart works harder during activity, and performing a physical task-the stress-may provokc abnormalcardiacresponses.A stresstest thuslooks at how the hean performs.How much physicalwork you can do, of course, dependsultimately on the amount of

21

oxygenyour body can use. But oxygenconsumptionis difficult to measure,Heart rate-the numberofhea beatsperminute rseasytocount and record,Sinceincreasesin heartrate roughly duringetercise.)oul prrallelincredses in o\'gen consumption although only approximate, heartrate is used as a convenient, measureof how much work you do during thlr stresstest If you have consulteda physicianwithin the last tew years, lhe chancesare good thal a slresstesl was recommenJedlo you. Perhapsthe idea of having a stresstest has occu ed to you evenwithout a physician'ssuggestion,sinceso much is said and written about it. Much of what you hear and see about stresstestingis,however,misinformation.Worse,manyo{thosc who perform and evaluatethe test apparentlyentenain misjudgmentsa. lo its \alue. rakenand 'n\alid Stresstestsare designedmainly to do two things: detector confirmthe presenceor absenceof heart disease,and establish a safelevel of exercisefor you. Strcsstesting does neither of thesereliably. It is, in fact, of very limited value and may produce misleadinginfomation, sometimeswith dangelousconThe various methods of stresstesting can be divided into and multistage.In a singletwo generalcategories:single-stage stagetest, your level of physicalwork or stressis kept constant testis the througlout th€ exercise.Th€ besfknown single-stage original MasterTwo-StepTest, which involveswalking up and down two speciallyconstructedstepsto increaseyour oxygen consumptionand your heart rate. The numberof times you have to go up and down the steps in a MasterTwo-StepTestis determinedbyyour ageandweight The older you are, and the h€avier,the fewer "tdps" over the stepsare required.In a singleMasterTwo-StepTest, you make the,prcscribednumber of trips in one and one-halfminutes;in the doubleversion,which is preferredby somebecauseit offers

25

T H E EX ER C IS E MY ' ]' H

a grcatertotal amountof exercis€,you make twice thc numbcr of trips and do it in twicerhelengthofrime. A further refinement is the augmentedDouble Masler Two-StepTest, in which you makc an addilional number of rrips up and down the stepsin thc samethree minutes10increasethe work load ofyour heart. A less-known,bur still occasionallyused.single-stage test is thc isometric hand-grip test. Here, sustainedsqucezingwith your hands provokes only some increasein hearr rate but a signilicantincrcasein blood pressure.Risesjn blood pressurc don t correlateas w€ll with oxygenconsumptionas increasesin hesrt rate do. so this tcst is the leasr valuable one. Since a suddenrise in blood pressuremay alsohave dire consequences for some cardiacpatients, rhis resl is generallyavoide{tif you are suspectedof having coronary disease. A multistagctest relics on succcssively increasinglevelsof activity.You exercisefirst at a low intensiryof effort, and then progressively at higherlevelsofphysicaleffort. you srayat each level of activity long enough (usuallyrhre€ minutes) for your body to achievean equilibrium or stcadyresponseto that level of activity. Multistage res(ingcan bc conrinuous,going from one level of efforr to the next withour stopping,or intermittent, with a pcriod of rcst after cquilibrium at each level of activity is achieved.Mosl multisragetestingtoday is continuous. Multistagestresstestingis usuallydone on a treadmill or a stationaryexerciscbicycle. The differcncesin rcsulrsbctween fte two kinds of apparatusare not grcat. and doctors often decidewhich to usemostly on the basisof how much they want to spendand how much spacethey haveavailable.But treadmilt testingdoes have the advantagesof using a farniliar mode of exercise-namely, walking-and of bringinginro usethe large musclegroupsof the hip and pelvic areas.The lreadmill also automaticallyregularesthe work level as long as you continue walking on it.

26

\ !IIAI

STR E!5 TE5 T5 D ON I

ITL L

In treadmill testing you step upon and then walk in tim€ with a moving bell. The level of exerciseintensityis varied by |he speedanci the slope of the treadmill. Tests usually begin wilh a treadmill speed of 1 7 miles per hour and an upward levelsof exerciseinvolve faster slopeof 10 perccnt. Successive speedand steeperslope up to a maximum of 6 miles per hour and a 22 p€rcentgrade. Usually, only enduranceathl€tescan perform at this maximum levet. Regularlyactivc heaLthymen can usuallycompletethree minules of treadmill cxerciseat 4 2 milesp€r hour and a 16 percentgrade Peoplewho are lesslit have. by d€finition. less capacityfor Physicalwork, and their maximumtreadmill pcrformanc€is at lower specdsand grades' ln bicycletestingyou sit upon a stationarybicycle.The intensity of the exerciseis varied by varying the resistnnceto pedaling.sincethe specdof pedalingis kept constant.Unlike the trcadmill, where you are forced to carry your own wcrgnl and the total amount of oxygcn you use for a given amountof effort will thercforevary with your body weiSht,you are sittrng on thc bicycle, so the total oxygen requirement for a given amount of pedalingis independentof your body w€igh1.But manypeoplcafe not accustomcdto vigorousbicycl€riding;their thigh and calf musclesbegin to cramp up or "turn to jelly" beforc they have hit the penk effort they might be capableof in someoth€r form of exercisc. The end point of a multjstaget€st may vafy. somc propo nentsof stresslestingadvocatewhat is called"maximal ' testing, which meansyou exerciseto that point where further increase in physicalwork does not causefurther ircreasein how much oxyg€nyou use or how fast your heart beats since heart rate is what is usualLymeasured,maximal exercisefor you is that levcl of effort beyond which your heart rate do€s nol rise any more. At this maxjmal levcl. normal people usually feel exhausted,and often nauseatedand dizzy as wcll.

27

w

qr

;.. I HE

EXERCI SE

M) TH

More conservativetesterschoosea..submaximal"end point for stresstesting. ln a submaximaltesr, an arbitrary end point is chosen,usualiya heartrate equalto 85percenrof the er?ected maximumheart rat€ for your age.Sincethe expect€dmaximum attainableheart rate decreasesas you get older, a convenient formulafor predictingaveragemaximumheartrateis 220minus age. Thus, if you are a normal 4O-year-oldmale havinga sub, maximalexercisetest, your predictedmaximumaftainableh€art rate would be 220 minus 40, which equals180;and 85 percenr of that is 153, which represenrsthe arbitrary end point of rhe If you are a patient wirh cardjacsymptoms,your exercise test is usually symptom-limited.That is, the test is sloppedwhateverthe level of exerciseyou achi€ve-when you report that you are experiencingsymptomsof your condition, suchas pain, dizzinessor brearhlessness. Somepatientsmay showsigns of abnormalcardiac function, such as pallor or unsreadiness. that can be noted by the examinereven before any symptoms arc felt. Th€ testis then stopp€dat thatpoint, evenif thc patient still feelscomfortabl€. Although your performanceof the physicaleffortis the basis of the test, and how you look and feel during the test is important, the examinerrelies more on observingand recording your physiologicresponsesto stress.Many kinds of r€spons€s can be measured,including the rate of your hean, its pattern ofelectdcal activity, your blood pressureand oxygenconsumption. Wher€as all of these responsesare m€asuredin a few technicallysophisticatedtesting cente6, in most tesringsituations only th€ electrical responsesof your heart (which autonatically give the heart rate) and perhapsyour blood pressure The electricalactivity ofyour heart is revealcdin your electrocardiogram,a recording of the electric signalstha! travel

W HAT STRESSTES'I 'SDO N"I ' TELL

throughthe heart.The heartcannotbeatunlesstheheartmuscle is electricallystimulated. Heartbeat is normally regulatedby electric signals,generatedwithin the heart itself' that travel through the musclescausingrhythmic, coordinatedpumping contractions.The electrocardiogramshowsall the electric signals,so it is very easyto count the numberof them and thereby know the heaft rat€. Analyzing more subtle asPectsof pattern and contour of th€ signalsas they appearon the electrocardi ogram is much trickier. To be honest, we don't even know all taken while a pcrthe rcasonswhy a normal electrocardiogram sonis restinglooks the way it does,and we certainlydon't have all tl}e answersas to why certainelectdcalchangesin the heart occur during exerciseor stress Nevertheless,through experiencewe have learned to recognizemany abnormalitiesand to judge with fair accuracywhat conditionsthey might indicate How detailedan electrocardiogramis dependson the complexity of the equipmentused.In all recordings'electricsignals calledelectrodes from your heartare detectedby sensingdevices that are placedon various pa s of your body A simple elecmay trocardiogramsystem,usingvery few recordingelectrodes ' that most abnorassumption be used on the generallyvalid malilieswill be deleded More elaboratcsyslem\'usingman, more electrodes,may be employed,however,sinc€it is known that certain abnormalresponsesmay be missedby the simpler system.Whethertheseabnormalitiesdetectedonly by the more is still elaboraterecordingsystemshave any clinicalsigni{icance debatable. continuouslyduring Sometestersrun the electrocardiogram period at the end ot a brief only exercise.while others record MasterTwoeachstageof a multistageiest. In th€ single-stage is not madeuntil immediately StepTest, the electrocardiogram Although more information exercise. the full complete afteriou aswell asafter,exercise during, maybe obtainedfrom recording

ir' i.

T H E E XE R C IS E MY TH

the "extra information" may be misleadingand lead to errors in interyretation. The electrocardiogramis also usually made duringthe restperiodafter exerciseb€cause,aslour crcunrory systemcontinues to readjust, abnormalitiesoccasionallybecomeevid€nt that were not detectedduring the actualexercise or in the first minutesof resting.Som€of the dearhsthat occur as a result of stresstesting-and deathsdo occur-hapDen in rheperiodtououingthe acruale\erci\e. Eventakingyour blood pressure,so simpleand standardized a procedurewhen you'rc sitting still, becomesa complicared maneuverduring stresstesting. Blood pressureis the actual pressureof the blood, measuredin millimet€rs of mercury, within the arterialsystemofthe body. With you bobbingup and downl scramblingto keep pace with a treadmill or furiousiy pedaling a bicyclegoingnowhere,it is very hard for someonero measure your blood pressureaccuratelywith the srandardcuff around your arm. Sometesters,therefor€.ignore your blood pressure alrogelher or rerord it onl) intrequenll'duringrhe tesr.yer, accuratelyrecorded blood-pressureresponsesto exercisemay be very helptul in diagnosingabnormaliriesof the h€a . In some centerswhere highly sophisticatedphysiologicstudiesare per_ lormed.a needleor catheterconnecred ro a sensirive presiure gaugemay be inserted directly into one of your arte es for drreclmeasurement ol ]onr blood pressure as )ou exetcise. The resulis of a test using an elaborat€electrocardiogram systemmay not be rcliablycomparedwiti resultsfrom asimpl€r one, just as differencesin ihe timing and the method of measuring either electricalor ptessurerespons€sgive the examiner different data from which to make judgments.Looking at one set of measurements,a doctor might feel that a patient had a perfectlynormal hearr. Using anothers€i ofmeasurements,he might be just as cerrain the sameheart was abnormal.These differencesin testing procedures,techniquesand equipment

30

WHAT STRESSTESTS DO N'1'TEI - L

affect the examin€r'sconclusionsabout the actual state of an individual'sheart. In spit€ of thesevariationsin data that can lead to diftlring interpretations,examinersassumethat stresstesting does accomplishits basic aims: to diagnoseor excludeheart disease and to measurethe perfonnanceyou are capabl€of. Most people "pass" their stresstest.Their cardiacbealthis certified,they are lold what "shape" they're in and they go off to buy their new athletic gear. When the bill arrives, they pay it willingly. It's worth th€ money to know they're well and that it's safe to exercise.But they dorl know that, and neither doestheir doctor. Just as important, when peoplewho "fail" their stresstest are told they haveheart disease,that conclusionmay be equally uncertainThe most common purpose of stresst€sting is to find out whether you do or don't have coronary heart disease.That's what the Committee on Exerciseof the American Hean Associationsays,tandthafs what mostdoctorsthink theyaredoing when they suggestyou take a strcsstest. Many of you considering havinga stresstest probably have this objectivein miod, too-to detect coronary heart diseaseif it is present.Inplied in this is the notion that if the stresstestdoesnot revealcoronary heart disease,then you can concludewith confidencethat you are frce from it. The trouble is that this conclusionis wron8. A stresstest doesn'tnecessarilydetectcorcnaryheart disease,and a normal test is not firm evidenceof the absenceof coronarydisease. A stresstest showshow well you can perform wh€n pushed to work hard during exercise.It is a test of function or performance.But coronaryhea diseaseis structural,a narrowing of the coronary arteriesthat carry oxygenlad€n blood to the heart muscle.It is not a diseaseof performance,and may not interferewith function at all. You can hav€nice,cleancorollarv

31

r! H E E XE R C TS E MY TH

arteriesbut a hearl that doesn'tperform wcll during hard work. You can have a hea that carriesyou througha stresstestwith flying colors but coronary artedesthat afe already constricred with fatty deposits. Even if your electrocardiogramand other measuresshow somethingunusualin the way you funcrion during a stresstest, coronary heart diseaseis only one of many possiblereasons, some of which are innocuousand don't indicate anythingone way or another about eith€r the presenc€of diseaseor how much exerciseyou're capableof. In facr, abnormalitiesin even restingeleclrocardiogramsare not at all uncommon.and are often related to harmlessand noncoronaryconditions.Mary physicianswill not do a stresstest if your r€stingelectrocardi, ogramrevealssuchchanges,becauseit is so likelythat rhe stress test will appearto be abnormal. Even if your restingelectrocardiogramlooks p€rfectlynormal, there are many conditionsthat can make your stresselec, trocardiogramlook abnormal. Abnormalities of heart valves, for example,may be associatedwith abnomat exercrsetests. lf you take certain medicines,for another cxample, rhe stress electrocardiogram may be abnormal.Anemia, with its low red blood cell count,can producean abnormalstresstest.And high blood pressure,too, may be the causeof abnormalelectrocardiogramresponses.Yet, with theseconditions,exercisewould not necessarilybe limited or proscribedio the sameextent it would be ifcoronary diseasewere responsiblefor the abnormai clectrocardiogram. Sometimes,if you have simply eatenwithin an hour or two of the stresstcst, it will look abnormal.This was the casewith a prominent businessexecutivewho is now chairmanof the boardofone of the major corporationsin the country. His stress test, reviewedat the requestof the companyunderwritingthe nsuranceaspectsof his potential appointment,was abnormal.

32

\IH A I STR ESs TESI S D ON 'T TEL L

Whenthe tcst wasrepeatedafter he had had no food for several hours, it was perfectly normal, and a major personaland corporate Problem€vaporated. The othersideofthe coin-the inability ofa normalexercise testto excludethe presenceofcoronary heart disease-is about ascommon.You can have narrowingof your coronaryarteries, even of sevcrcd€gree,and respondnormally to a stfesstest. Sometimesthe techniqueof recordingtb{) exerdseelectro cardiogramis inadequate,or the testhasbe€nstoppedtoo soon, beforeabnormalresponseshave a chanceto emerge,but there are many other reasons.An old heart attack might preventthe signsofcurrent coronarytrouble from show electrocardiogram ing up. Also, the resting electrocardiogmmpatterns of some to stress.Finally, just as peoplecan inhibit abnormalresPonses some medicines can produce abnormal stress electrocardi ogramsin the absenceof coronarydisease,so cancertainmedicines prevent an abnormal stress electrocardiogramin the presenceol cofonary hean disease. An exerciseslresstest cannot achieveits major goal of ac_ curatelydetectingcoronaryartery diseaseor ruling it out in any givenindividual- Although the directorof a well-knownexercise testing centcr suggeststhat it gives "an indirect image of the hxsnarrowedthe individualcoronary extentthatatherosclerosis vessels,"exercisetestingreally givesonly very lirnited and non' responses to one specificinformation aboutsomecardiovascular form of stress.Stresstesting is delinitely an imperfectway to detector excludecoronary disease,but proponentsarguethat it might neverthclessbe reliable €nough. What degreeof reliability can you as an individual put on the result of your test? One way to check a test's reliability is to seebow sensitive it is-how often it really picks up coronary heart disease.A perfectlysensitivetestwould pick up everycaseofheart disease, and would be 100 perc€nt sensitive-If the test picks up 90

33

q T H E E XE RC TsE MY I It

abnormalresultsout of 100 people with coronary diseascthe sensitivityis 90percent.A secondwaytochcckatesr'sreliability is to see how specificit is how often a normal result reallv indicatcsthat lhe nersonrs tree ol corondr)Lliseaee. Wirh a p€rfectly specifictest, everyonewho showed a normal result would havenormal coronarya eri€s,and the testwould be 100 perc€ntspecific.ff 100 people do not have coronary disease, and 90 of them have a normal tesr, the spccilicityof thc test is q) percent. An abnormalt€stresultiscalleda "posjtive" result,meaninS somethingftdr been found. A normal tcst result is callcd ,,negative"-nothing has been found. Peoplc who have coronary diseasebut have a negativetest are said to have a "false neg ative" test. Peoplewho do not have coronarydiseasebut have a positivc test are said to have a 'false positive" tesl. If 100 people have coronary diseaseand 90 of them have a positive or abnormaltest, and 10 of them have a negativeor normal test, then the sensitivityis 90 percent, and the false negative rate is l0percent. L'kewise,if 100p€opledo not have coronary diseaseand 90 of them have a negativeor normal tesr, and 10 of them have a positive or abnormal iest, the specificityis 90 percenl, and the false positiverate is 10 percent. Many studieshave been don€ to determinethe sensitivity, the specilicity,th€ false positiveand falsc negativeralcs in exercisestrcsstesting. Sensitivityhas been estimatedas low as about 40 percent and as high as over 90 percent; usualtyit's consideredto be about 75 percenr-ln otherwords, the testdoes pick trp 75 perc€nt of people who do have coronary disease. But the remaining25 percentof the people with coronarydis€ase show nothing unusual in their stresstests, so the false negativerat€ is 25 percent-In studiesthat have reported the least sensitivity,the false negativerate is 60 percent,meaning the testmiss€s60 out of every 100peoplewho do havecoronary disease.

34

I WI t Al'S'I 'RESS TESTS DO N'T TELI ,

Figuresfor specincityof stresstesting have also varied widcly, from as low as 65 percentto as high as 95 Percent.If we're to believe the low ligure. 65 percent ol normal pcople show a normalclectrocardiogramin theil strcsstest, but 35 percentof thesehealthymen and women, without coronarydisease'have a falsely abnormal or false positive test. Reporl€d figuresfor falsepositiveresults-abnormal testsfornormal people rangc from 5 percentto as high as 35 percent.And in certainspecial noncorcnarysubgroups,such as wom€n with a minor heartvalve abnormalityand normal coronary arteries,positivetests havebecn recordedfor as many as 64 percenf. This tremendousvariability in thcse test results must' by itself, suggestsome real problems, not only wilh the actual reliability of strcss{estingprocedures,but also even with how to figure out reliably how reliable they are Worsc. this variability of resultsxndelarlimalesthe problem of reliability as far as you as an individual are concerned.Most studiesof sttess testinghave involved peoplc known to have, or stronglysuspecledol havinS. coronaryhearldi'earc lf you lcsl d grouPol peoplemost of whom probably do have the diseascyou're testing for, then obviously most of the positive tests will be true positives,sincethe people do, in fact, have the disease.But if you testa groupofpeople mostofwhom do not havethe disease, then many of the positivetestswill be false positives. lfyou as an individualknow that you havecorollarydrsease, or stronglysuspectit, then a stresstest addslittle ot nothing to your knowledge;a positivetest would be exPected'and a neg_ atjve test would be highly suspectof being a fdlse negative lf you haveno r€asonto suspectyou have coronarydjsease'then the reliabilityofa stiesstest is particularlypoor, sincea posrtrve testwouldlikelybe alalsepositivq and anegativetest,although expected,could not excludethe possibilityofcoronary disease. A studyfrom the NationalInstitutesof Health isparticularly Among 39 subjectswho had no symprelevantin this regard.'?

J5

TI T H E E XE R C ISE M Y TH

toms of heart diseasebut had abnormal stresstests, only 36 percenthadsignificantcoronarydiseasewhentheir arterieswere examinedby specialx-raysafter dye injectionsdirectlyinro the coronarycirculation.The resultsin 64 percentof their positive or abnormalstresstestswere simply wrcng for the diagnosisof significantcoronary arlery disease.A similar study by tlrc United StatesAir Force found 75 percenl false posirivestresstestsin peoplewithout symptomswho n€verlhelessunderwentexercise testing.r Stresstestingin women is especiallymisleading,for reasons that are not the l€astbit clear. In somestudies.more rhan half the positivestresstestsfor coronarydiseasein women are fatse positive,indicatingdiseasewherenone exists.Women might as well tossa coin to seewhetherornot they havecoronarydisease as r€ly on the resultsof a traditional stress!esr. Another measureofa test'sreliabilityis its reproducibiliryhow often resultscome out the samewhen the test is repeared. To considera test a reliable indicator of anything,you should expectthat repeatingthe test under the same conditionswill give results that are very similar, if not identical, each time. Imaginean IQ test in which you got a scoreof 80 one day and 150the next. Sinc€intelligencedoesn'tvary much from day to day-and neither does the condition of arreries test results that fluctuatethat way have no meaning.A measureof some, thing must be repmducible,or elseits validity as a standardor measureis compromised. When the questionof reproducibility of stresstesting has been addrcssed,the resultsare dismaying. Analyzing the occurenc€ of inegularities of the hearr rhlhm during exercisetesting showsthat reproducibilityin two consecutivetests in the sam€ individual is about eoual to reDroduc'brlir'by chancealone.'If you testthesamegroupof people repeatedly,different membersof the group will have arrhyth-

36

WHAT S'I'R ESS IESTS D ON 'T TEI- L

mias on eachtest, Testsdone as closeas 45 minutesapart ancl thosedonc months and yearsapart show the samelack of re' producibility.5 Perhapsthemost lellingreport wasdeliveredat the scientific 6 sessionsof the Amcrican Collegeof Cardiologyin 1977 The purposeof the study was to assessthe reproducibilityof the most abnormal stresstests, the tests that suggestedthe most severedcgreeof coronary disease.Of 34 subjectswho had at l€astone severelyabnormaltest, only 14 had reproduciblyab_ normal stresstests,while for the 20 other pcople the severely abnormalr€sponsecould not be reproduced.And in 11 of these 20who did not havereproducibletests,at leastoneofthe repeat testswas actually normal. Thus, only 41 Perccntof markedly abnormalstresstestswere reproducible,and 59 percentwere Much as any doctor and that includesme-would appre ciatea foolproofway to checkeasilyfor coronarydisease,stress testsare rot sensjtiveenough,specificenoughor reproducible enoughfor anyone to bc sure they'r€ telling you anything at all. At most, a stresstest might have somevalue in confirming a diagnosisalready arrived at by the conventionalmeans of carelull)rahinga palicnls medrcalhislory The best analysisof whether a stresstest providesusable additional information for you or your physiciancomesfrom Victor Fro€licher, formerly oI the United StatesAir Forc€ School of AerospaceMedicine and now with thc University of Cali forda,SanDiego.'Dr. Froelichersummaizedseveralprevious studiesofthe accuracyofdiagnosingcoronaryh€artdiseasejust from the patient'shistory-the symptomstbe patientrelatedto hisphysician.Diagnosisofthe prcsenceofcoronary djseasewas accurate90 pefcent of the time from symptomsalone. In patients with no symptomslike those of coronary dis€ase'thc diagnosisof abscnc€of coromry diseasewas correctin 95 per-

37

l TTI E ETERCI S E

MY I H

cent of the cases,while jn 5 percentrhcre was latcnt or hidden coronarydtscase. Dr. Froclicherthen calculated,basedon averagesensitiviryt specilicityandreliabiliryligrres. how muchmorecertainlycould be achievedif a stresstest were done. He conclucledthat a posrttveor abnormalstresstesl for a patient alreadythouSht lo havecoronarydiseaserhroughsymptomsatoneraisedrhe prob abilily of rhe diagnosisbeing correct from 90 percent io 98 percenr.A ncgatrveor normal stresstest in a patient thought to havccoronarydiseaseloweredthe probabilityofthe diagnosis berngcorrectfrom 90 percenrto ?5 percent. In patientswith no symptomsat all, a positiveor abnormal "tresslcst raiscdthe probabilityofhiddcn coronarydiseasefrom 5 percentto 27 percent, while a negativeor normal stresstest reducedthe probability of coronary diseaseftom 5 percent1() 2 perccntAI firsrglance.rhechanl(sin probabitir)ot hdvrngco,ondry . dr\ca\ehrsedon re\ull\ ol srreesrcstingmighl loot .ignificant and,to an epidemrologist concernedwith hugegroupsofpeoplc. they probably are. Bur think about yoursetfas an individuat. Sincethere arc so many falsepositiveand falsenegativetesrs, no individualcan tell if his or her own test is a true positiveor lrue negativeor falsepositive or false negative. If you have a history lhat indicarescoronary hcart disease, you alreadyknow thc probability ofyour reallyhavingcoronary diseaseis 90 percent.A positivestresstest that raiscsthe prob_ ability to 98 percent doesnt rcally change anything. And a negalrvcstresstest only means thar the likelihood of really havingcoronarydiscas€is som€wharless,but it is still 75 per_ cent. ln either case,you,d probably plny ir safe and conduct your lifc on the assumptionthat you're likely to have coionary By the sametoken, if you have no history ar all indicating J8

WH AT STRE: SSTESTS DO N'] 'TEI 'I -

coronarydisease,and thc probability of really not having coronary cliscaseis about 95 perccnt' an abnormalstresstesl only meansthc probability of not having coronary diseasers somcwhat reduced, but it is still 75 percent' In other words' the chancesare still three out of tour that you're quire well and needn'tworry about having coronary disease'bccauscthe tcst is likely to h.rvc been a false posrtrvcOn the basis o{ your medical history alonc aR accurale dis' enoughcstimateof the likelihood that you harc coronary easccan be made. A strcsstcst docs not offer signilicantadditional information-il may ofter only additionalconfusionand is thereforequrte unnecessary' But let us assumeyou urdergo a stresstest A positivcor .rbnornrrlIesl i\ uh\iousl)ol grealcrcon\ernlhan r negrli!e or normal onc, So. let's assumcthe resulls are abnormal You are now faced with the qucstion of whether the abnormal test is a truc positiveor a false pos'trvcone You havc a few options in this circumstance,bul none are very satisfactory.First. you may decideto ignorc the lcst result and rely on the informatjon you had about yourselfbcfbre the lnd test. lf this is your choice. why did you spendyour trme moneyto have thc test in the first place?And you may be lett' the as many people arc, with a naggingsenscof anxietyabout underlyingcondition of your heart' A sccondchoice is to h.rve a repeal stresstest Whocver conductedyour lirst test would probably willingly do anolher' is After all, it's your time and your money But reproducibility problem same the so Door that You'll be stuck with essentially positive aft;r the repcattest. Ifthe repeatis positive'is it a true was or a false positivc? lf it is negativethis iimc which test you correct,the lirst or the second?No matter how many tests questionablc undergo,thcir retiability is Further choicesin following up abnormal stresstesls are

39

T H E EX E R C IS E MY TH

radronuclde scanningand coronaryangiogrdphy. the 6rsl in_ vot\esIntecrrng radioacrive materiatrnto the bloodslream and following its coursethrough the heart or corona.y circutation. Accuracyot \ome torm\ ol \canningi\ nor much be er than lhdl ol reguldr5tressresting.\ewer scanningtechnique\ are mole. acrurate brlt the cost may be over $500. Angiography usuallyrequireshospjralization,becausetubes a." ini"rt OAi_ rectl) inlo the hrafl and coronar)aneries.Dearh and senou. nontatat,complicarions occurin a .mall percenrage ot patients. Eestoesthe detecttonot exclusionof coronar! hedrt dis_ ease which it fails to achievercliably_the other major aim or exercisetesting is to find your €xercisecapacity and what level of exerciseis safe for you. The Committeeon Exerciseof the AmericanHeart Associationadvisesthat,,exercise intensity that is both safeand effectivemust be basedon the individuali ex€rcisetoleranceor capacity. . , a measurcmenr or accurate estrmateof individual tolerance. . . is an extremely us€fulaid ro choosin€ rie properinlensil'ar the beginning of dn erercise program. I he commirtee addsthat..exercise rnlensity mustbe regulatedperiodicallyduring t]le succe€dingstages,, of an ex_ erciseprogmm.3 In th€ir exercisehandbookfor physicians,the Heart Asso_ . crarron ateosa]slhal ..indiriduals who completete(ting$ithour elnrhrbngabnormalECG letecrrocardrograml responses or orher e!roenceol orerl or subclinrcal hearrdisease can be nedica ) authorizedto take part in unsupervisedexerciseof an intensity lhar doesnot e\ceedthal achievedduringlne ctearance test,.. In ornerword\, according to this.it )ou oncecompleLe a mdrrmarstresstest to the level of exercisewhere your heart rate andoxygenusagecannotincreasefunherdespitemore exercise, and you don't show abnormalresponses,then you canteel safe In pu(hrngtourselIto rhat levelreguldrly.lt ]our tesri( a sub. maximat one.ea'. ro 85 percenr of rour age_predicted marimum

40

WHAT STRESS'TESTSDO N'T TELL

heartrate.tben this levelofexercisemay be regularlypedormed wrrhimpunil'. your This is a sptendidideal-the accurateestrmatronor oi inalividualtolerancefor stress.and the periodic adjustment is an it Unforlunately cap,tcity your chanpng vouraclitity lo .turive one. I fulll subscriheto lhe ideal bul I drsputelhe so Committeeon Exercisewhen it implies that even the most ererciserestingcan achieve phi\ticaled.monilored.multisrage

ir.

lf vou acceptIhal slrerslestinggive\ an acculaleestlmale you're as' of vour toleranceor capacityIor physicalexercise' that sumingthat your exercisecapacityis fixed and stable But isn't so. There are lots ofthings that can changeyour responses are to the sameamountof physicalstress Someof tlese things Other drinking' under your direct control: smoking, eating, things, perhaPsbeyond your control' arc equally important: temierature, humidity, air quality, worry, anger' depressior' re_ AII of these can significantly a{fect your cardiovascular cycling' to running, sponsesand your generalbody reactions you like aerobicdancing-whatev€r kind of vigorousexercise It s naivelo assumelhat you ll al*als respondto e)\ercise your the same way you did in the controlled envircnmentot an austresstest, You can't run in 90" heat the way you can ln you ve lust conditionealoffice- You can't play squashas well if toslow Andcigarelleshategot poli\hedoffa poundol lasagna vou down on the tennis coult The vogue today is for physiciansto "prescribe" exelcise' especiallyior cardiac patients, much as they prescribemedipe cations,with specific"dosages"basedon stress-test ormto precision of scientilic ance. This lends an unwarrantedair idea srre\\teslingand addsto lhe credibrliDof lhe erroneou' that exercis;is medicallybeneficial But it doesn'talter the fact 41

-r ,I' H E

EX ER C TS I MY T]I

that lour cardiac and orher responsesro a specilicamount of physicalactivitv vary with circumsrances. Thcse rcsponsesmay be enlircl\ and Llangeroush unpredr(tahlc. A rragLtrLre.ror\iltu\rfdrc.rh( pornl.A t$ent) \e\(n_)(Jf_ ., oroman$ hu r\(rcN(J rcgula,l!dndrencaredl\ undcrucnt mJI_ rmal stressteslswith normal rcsultssufferedcardiacarrest run_ nrng on a track where he had run ofrcn for yea^. lle ncver exceededthe levei of exerciscthat he easilyachicved in stress testing- We learned larer thal he had had severaldrinks the night before and had slcpr poorly tbltowing an argumcnt wrth hrs estrangedwif€_His responsero exerciseon that faleful day was not predictedor even suspectcdbJ, any tesr he had ever had. Nobody cver lesredhim under his .,reallife,, conditions. nor ls it possibleto do so. Actually, stresstesting itsclf caries risks. you,1l note that you're asked to sign a releaseform before a rest, indicalion enoughof at lcasrsome potentiai danger. l.he largest srudyof nsks.rssociated with stresstesringin the United Sratesappe;red in the Journalof th. Ameri.an Medicat Associstionin l9jl, and hdicated l dcath per 10,000tesrsin a survcy of 170.000 rests performedar variouscentersaroundtbe country., Whenserious nonfatalcomplicationswere includcd, rhe incidencerose to 2.5 morbidc\ent\per lU.oUU te\r,. A lafgerdndmorc reccnr.ruLly lr om.WcstC(fmrn) rcpo cJ tcomplicalronIn e\cry /.)r(l excrcisestresstesrs.','Usingthe I in 7.500 ligurss, ifjust the estrmated30 miltion joggers in the United Statcseach had 1 \lre\\ lcsl )carly. $e could rntrcipirc 4.oUU\uLh dangcrou\ Incroenrs. A murer(cenlAmericansrudtcoverin!t.175cenrer\ \ho\ed complicatron, pcr I0.U00rc\ts: on. t,t rh( aurhor\ ^.86 ol lndlsluLl)repo(eLll deathsin hrsoq n ,efl(sol l0,0UUtens.l ln all likclihood, the figuresare but the rip of rhe iccberg and underestimatethe dangersbecauseman), unrowaro evenrs and complicationsare not publicly reported.Also. many stress 42

I WI I AI ' STRESSl ESTS DO N'T TELL

rsron lestsare probablyperformedwherePrcparationafld supe are likely are not;ptimal, and statisticsfrom suchtestingsites to be wo;se but to 8o unreported More tragic' a signilicant numbcr of the reported deathsand lifc-threatenfg complrcations occurto peopLewhosecoronaryarteriesare subsequently shownto bc normal If you still assumethat stresstesting givesan accuratces' timat;of how hard yoLrcansafelyexercise'then it's only logical the ihat you be willing to spendyour time and money' and take capacity risk, of periodicallyupdatingyour stresstest' Exercise can diminish as well as increasedne to a variety of cnuses' includirg illnessand inactivity lt lakesjust a short time a few davs to a few weeks at most-to lose most or all of the con ditioningbenefitsofphysicaltraining' and you shouldbe willing to be reiestedafter any significantinterruptionof your exercise routine and periodicallyduring any exerciseprogram-at $150 Of course,few peopleundergoregularlyrepeatedstresstest_ inel$h\ shoulJthey$hen lhe) hcJr tlom all :rde\lhal excrci\e pt.'.n, lhe ver! di'earc rhal rhe lcsr is supporedro ',.i.tr"ittArmed with assurancethat th€y do not have coronary detect? arteN disease,most patientsleavethe ordealoftheir first stress test io embracewh;tcheart€dly what they b€lieve to bc the protectionof exercise.

43

.--

l1

T H E C ASE AG AIN ST L ON GEVI'I'Y

TheCose ogoinsfLongevify Longevityis the most compellingof the promisedprotections of exercise.Millions of today's exerciseenrhusrasts. s€duced into the latest warm-up gear, designerlab€ls stickinqto their sueatingbodies.run. dance.srrerchand slrainin rhe-hope and erpecralron of Ii\,inglongerlires. But despirerhe wide;pread notion that physicalexercisecan add yearsto your life, there is no reliable evidenceto prove it. Biologicalagingis a fact of life. Although som€res€archers concludethat we have a biologicalpotentialof up to 110or 120 years,living that long is so rar€ that most scientistssettlefor a biological limit of about 80 years, barring extraordinarynew andfundamentaldiscoveriesabout the humanorganismand the agingprocessitself. We think of ourselvesas living longer than our forebears, _ but in fact the biologicallimit hasn't changed.Tombstonesin eighteenth-and nineteenth-centurycemeteriesare witnessto

the frequencythen of infant and childhoodmortality' deathsin epidemicsand d€ath in childbirth But the agesof those who djd reach"old age" are not differentfrom agcstoday Advances jn medicineand public heatth havc primarjly extendedthe 4reraS?life expcctancybyallowingmor€peopleto reacbtheupper limit of thei biological potential. A larger proportion of the populationreachesold age these days' but the upper limit of (wo iife expectancyhas not bcen dramaticallyalfered- lf the disease and canleadingcausesof deathtoday-cardiovascular cer were conquered, overall life expectancywould still increaseby only a tuw Years. Given the biological limit to longevity' the likelihood of attaining that age depends upon many things. Diseases,although dificrent ones from those that took our lbrebean to early graves,are still important. But other, less tangible' circumstances,generally lumped under the iabel "psychosoc'al variables,"seemto matter as much, sincethey affect mortality to a large degree.For example, at any given age more tban twice as many people from the 'lowest" social classdic as from the "high€st" social class And mcn with lcss than eight years of schoolinghave a 50 Percent higher death rate than thosecompletingone or more yearsof college' Becausepsychosocialvariablescan exert a large influence on any analysisof mortality, a valid study of the relationship betweenphysicalactivity and longeviiy must take a long list of them into account.Studiesthat don't-and that is ncarly all of them-are simplisticand unreliable Besialessocial group and educationalstatus,thc best_documentedpsychosocialvariablesthat influencelongevrtyare lncome,oc.upationalstatus,work satisfaction,socialactivity and life satisfaction.People who are more prosperous'who hold higherlevel positions,who find their work and their socialliv€s interestingand gratif!'lnglive longer!

-.r lHEE\ ERC] SEM Y I H

Social intcraction seemsto be one of rne mosr lmportant predictorsot longevity. Men and women with the mosr social conncctionslive longest, while those whose lifestylesisolate them from other people are more likely to rjre sooner. The elderlychurchvolunreerwho bustlesabourat the churchbazaar is likely to bc living longer becauseshe is socialtyactivc. not becauseshe is physicallyso. Marricd peopte live longer than the unrnarried,the widowed and thc divorced.Even persmay providca form ofsocialinteraction;peoplewithpets live longer, An underlyingrcason mry be that pl€asantsocial inrerac_ tions icnd to reducestress.Slresshas beenglaringlyimplicated as an unhealthyingrcdienrin our lives. Alrhough s few p€ople seemto thrive on stress,and a moderateamount of pressure may havesomcbenelicialeffcct.largcr dosagesfor most people can producedestructivechangesin their bodies,hormone and other chemical balances.Thcse changesmay, in turn, affect susceptibilityto diseaseor hamperthc abilily to fighroffdisease once it occurs.The first year of retirementand the first year of widowhood-hard times for all of us-are both associated with a lump tn mortality rates.Even the surprisingparallcl ofhighcr death rates with unemploymentprobably hasits origin in tension-relatedillnessand physiotogicalvutn€rability.A study of 1,200ccntenarians,Americans from farmers to bsnkers who lived to be at lcast onc hundrcd yearsold, showedabsenceof stress,for whatcver rcason, to be the most fundamenralcommon denominalorin their long lives_, Heredity, nutrition, habits and €nvironmentarc other lac tors that affect the lcngth of our lives. If your parenrc.your GreatAunt Matilda and your crandfather Jonesall lived to bc ninety, you can make a fair guessthat longcvity..runs in rhc family-" Whar you eat and whcther you smokeor drink alcohol in morc than moderateamountsaffcct health in general,and

THE CAsE AC ATN5T LO NG E\ 'I T1

person thercfore longevity. MortaLity rates vary by where a lives,partly becauseof suchfactorsas industrialpollution' but also becauseof such measuresas thc pacc of life, the social integrationpossiblcand the extent of communltysuppon systems of all kinds. Clearly, thc issu€of longevity is erormously complex So \cr) man\ lhing\ 'manyof t\hich are poorl) unJ(r\loodanLl tpan life lhc preJi(lrng lhal .litficukto mca.ure- rre in!ol!ed is of anv individual is virtually impossible lf narriagc itself jusi as welll And if Drote;dve, cloesa "bad" marriagework ;ot, how happymust the marriagebe' and how do you measure that? A penon might be delightedwith his job as a coal mrner' but easilycontract"black lung" in his forties Mrs Srnithmight volunteerfor evely committecin sight out of stridentcontempt her for the incompetenceof her co-workers.so that the fact of interaction' social of her mcmbershipis a poor measure Into this morassof ill-delined and unquantifiablcelements tr has been dropped the complicatedquestionot exerciseand that relationshipio longevity However ill-foundcd ihc idea Children' compelling is exerciseis protectiveandlife-cnhancing .rrn about alt day, strike us ns 'full of lifc," and we *ho "an " sayofan activeolder personthat shcis "brimmingwith vitality wh"n *e ure full of life' it often brims ovcr in the form of the activity.What is more logical,then' than to build from this is The idea person? a nolio; that cxercisep /J more lifc into an " rs acceptedby most people as a biological"given There alm;st una;sailablebelief that exerciseaddsmore life and that jdea has a simple and we will therefore not die so carly The quijlil) inturti!( logic.a \cducltve.mrgical Studjesof the relationshipbetween physical activitv and dismortality alealalmostexclusivelywith death from coronary leadease.and with good reason Cardiovasculardiseaseis the any measurable dnd ing causeof death in industrialized societics,

tl T H E E XE R C ISE MY TH

I

impact on life expectancywould have to affect a major cause of death. Physicalactivity is, moreover, dependentupon the cardiovascular systemat lcastto the extentthar the heartpumps the blood and the arteriescarry it around the boay so ttre ceils €an useth€ oxygenin it to provide energyfor activjty. No one has even suggesteda link betweenphysicalactivity and other major causesof death, such as canceror car accidents, Researchin this area is thoroughlyconfused.In study after study of physicalactivity and mortaliry, tesuhsare so contra_ dictory that any conclusionthat could be drawn from them amountsto no more than unsubstantiated opinion. The specificbelief that exercisemak€s you live longer becauseit proteclsyou from coronarydiseasewaslirsr legitimized by Jeremy Morris's 1953landmark study of l-ondon transporr workers. Morris analyzedthe health recordsof about 31,000 male London tmnsport workers, agesthirty_fiveto sixty_four years,in order to "s€ek for relationsb€tweenthe kind of work men do . , . and the incidenc€amonglhem of coronaryhear! disease."The workerswer€ dividedinto two occupationalwork groups,conductorsand drivers. London bus conductorsare a pretty active group; they swing up and down rhc stairsof rhe doubl€-deck€rs,help litrle old ladies on, rush to tell people where to g€t off and manage to collect all the fares in the meantime;the drivers, on the other hanrl, just sit behind the wheel and drive. The resultsof the data analysjsshowedthat conducton had less coronary hea.t diseasethan the drivers; when the diseasedid appearin conductors,it wasat a later age andwaslesssevere;and conducrorsliv€d longer.Mords and his colleaguesfocused on the greater physical activiry of ..con_ ducting" to explain the lower incidenceand mortality of coro_ nary heart disease. Physiciansquickly acceptedrhese conclusionsas scientific fa€l. The impact was such that most subsequentstudiesof rhe

48

Y

THE CASE AG AI NST LO N C EVI TY

relationship between activity and coronary diseaseand longevity, event;this day, cite Morris's originalstudyasa foundation lire force of the "facts" was so great that, althougb Motris and his co-workersrepudiatedtheir original conclusionswithin only three vears-we shall see why-others still sought to confilm what had never been proven in the first place SuPportfor the ialeathat physicalactivity enhancedlongevityand reducedcorjournalsdur' onarv hearl diseaseappearedregularlyin medical prolession medical ine t;e lqoos.By lh;follo\ting decade.lhe wis, literally, off to the races. In 1962,H. L. Taylor, of the Universityof MinnesotaSchool of Public Healtb. analvzedrecordsof 191'609men employed in the American railroad industry' an industry chosenbecause it offered "favorable conditions for study "r Railroad workers rarely changejobs, so the effectsof other occupationalinflu' *ces are minimized. Since detailedrecordsar€ usuallymain' tained, data on death rates are consideredteliable Taylor's analysisshowedlower death ratesfor more activepeople,supporting the idea that men in sedentary occupations have more coronarv heart disease than those whose work requires moderat€t;heavy PhysicalactivitY An analysisof about 110,000adults enrolled in the Health lnsurancePlan of GreaterNew York, and classifiedby activity a levels, was pubtished in 1969 The least active group had twice the risk (8.5per l,m0compared with4 2Per I '000)of suffcring a 6rst heart attack comparcd with the next adrve group; ano dvins ftom that heart attack was also more likely for the least activeindiviauals.he aifferenceswere only betweensedentary men and those moderately more active Therc was no firrthel decreasein risk for more actrvePeople In 1975,Dr. Ralph S Paffenberger'Jr', of Stanford UniversitySchoolof Medicine,analyzedthe healthrecordsof6'351 5 San Fmncisco-arealongshoremen Trying to corelate worK

49

t I' H E EX ER CIS E M Y TH

enefgyexpenditurewith coronaryattacksand cotonarydeaths, he found that only thoselongshoremenleadinga very energetic work lif€ had significantprotectionfrom coronaryaltacks;lesser degreesof eneryyexpenditurcwere not protective. Dr. Paffenbergerlater analyzed16,936questionnairesof supposedlyhealthyHarvard alumni who had enteredthe school from 1916to 1950.6He estimatedenergyexpenditurefrom the activitiesthe respondentsreported-everything from reading to squash,from doing nothing to distancerunning and competitive team games.The data reportedly indicatedthat highlevel energyexpcnditurewas protectivc againstfatal and nonfatal coronary heart disease,but anything lessthan highlevel energyexpenditurewas of little or no protectrvevalue. About 20 years after Morris's appealingfindings,the popularityof runningbeganreatlycatchingon Sincethe 1972Olympic Games,when millions of tel€vision viewels saw Frank Shorter becomethe first American in 64 years to win the marathon, interesl and involvement with running gr€w. The New York Road Runners Club. which had started in 1958with 42 memben, had, by 1976,some 1,700members;it now numbersabout 22,000.Thc 1970New York Marathon attractedonly 126 runners.and almostfive times that numberten vearslater. In 1975, th€ New York Road RunnersClub beganclassesand clinicsto promotc and provide instruciionin running. A highly successful m^Eazine,The Runner, began publication in 1978,and three books on runnirg were on the N?, yo,'k fimes best-sellerlist for much of that sameyear. In the runningglory daysof the 1970s,a quite extraordinary idea was introducedto the medicalprofessionand then, rather quickly, to the running world at large. Popularlyknown as the "Marathon H'?othesis," the notion was formulated by Dr' Thomas J. Bassler, a pathologist in California As originally proposedby Dr. Bassler. himself a devoted mamthonel, the

50

I TY THE CASE AG A'NST LO NG EV

protecconferredabsolute thesisstatedthat marathonrunning h(ar(direr\e a.rtr' flom coronary ,ii" wa' Hyptrthe'is ""'o"?"" """i"" tn.-.^",", y'ars ine Mararnon peopre ienned anJredennedasvarious ;"i;". .""iJ;;i rbe or den) one or anotherpropocition ;:;;; Bir\rcr ';:;il" ,'i"' p"'rrr iromrhetacrtharDr' ;;li';;;;;,1." word' distrenr wirh bur Iepearedlv *ur,.u ,n' i**iii^ 'Jeaoltginallv'thepropo\ition 'eemed ,"d-ut a'u"*"i due dealh "'ona'iis one lrum prote(ls rr\clt t"nrng-v''' ,.i" *ri."**." roru' IecentrvDr' Bassrer's ai*u'" ;;,l,n;,il;; runn\'r' mararhon thc n. ** cltdrl'thelileslllcul ir. rhi' remarkahk "i""*"a, irs(lt wirhcnnrcffins ii. ll*.' '"""'* 'i'"" person$hoselile'r!hpermirr iir. " " , , i o . . " , u , " t t " h r m a n ) t"-utlometerrace-a lmditionalmarathonnilni. .i.ot"" orher\hd\e " atrel''lisease i" uv ttomcorondrv i. "C *en ldrrherafi(lLtBelieve or nor'even rr '.rn""i ir'. p-p"'i,i"" i"lf" marathonrunnrng ti"l.ii.n a i..o.taity asa conscquenceof sugge:ted has '" heen in lusl the subMorris\ originalpublrcati"n r;;.. andlgT0sand ":; lqbu' the ,.0u.,i,,ppu,.n'*"n'marionsduring Hlpnrhe'r'a dccrdedgo' ,nll'l*j,i. ,to*t t theMrrarhon \^a\ frrml\es,i. ii", ii", pin *r acri!ir)is trte-enhancins lone$d! rrt..^. lor longevil)hadcomca r"iri'rt.,t '-"i"iuit""iv itndmagrcar logical upp""rlngideasthathaveboth it ditnculrt" risfel Bur \rilr 'eem' r,"l;,1; p;;;il arc r"oo lvefcnor'ublccted ideds lao in ,",ro.p".,tr't 'rte'e'tudie\anJ wasnot givento credcnce t"Ji rnor"..iti."f "y" "nd that more betweenphysical s"i.ifu..t"ai.. tftutilf"A to showaconnection rirecourd erenshowedthata strenuous ::ili;il;.;;;;i, "r

*'^,ll".il \,ud! o'sinar b! Morri,. iil'i'i,lilll.ms
I THE CASE AG AI NST LO NCiEVI TY

T H E EX ER C IS E MY TI{

wasbecomingrecognizedas an epjdemicof coronaryheart dis ease,it was within the powei of each of us to prevent this epidemicfrom spreadingto thoscwe caredfol and to ourselves. This easyanswer-be more active-was too appealingto generatesufficientcontroversyand conflict. But there were reasonsenough to questionthe validity of had reached,if only that the exerciseenthusiasts the conclusions anyonehad wanted to. From the beginning,Morris and his colleagueslisted othcr possibleexplanationsfor their bus driver and conductordata and w€re quite honestin announcingtheir bias They choseto focus on the "greater physicalactivity of conducting" as the causeofthe lower incidenceof coronaryheart diseaseand morthe otherfactors tality inthatgroup, and "decidedto ignore history that must in the constitution of the men and in th€ir 'fhese "other factors" they listed certainlyalso be involved." but choseto ignore included: "diffelences in the constitution and early experienceof the conductorsand drivers, another expressionof which is that lhe men selectfor themselvesthese very diffcrcnt jobs." These"differ€ncesin the constitution" and the consequent of different jobs by different people are, in fact, self-selection centralto a critical analysisof Mods's daia. For, as he himself found and publishedin 1956,only three yearsafter his original repo(i the conductorsanddriv€rswerereallynot similarpeople from the outset.rThe bus drivers were fatter; their girth and weight w€re greater than that of conductorseven at the trme they were 6rst hired. And if b€ingfatter went alongwith things like higher cholesterol levels and blood pr€ssure,a6 seemslikely, then thesecould have explainedthe differencesin the risk of / dying observedlater. This self-selectionof certain occupationsand activitiesby peoplewho alreadyhave certainchancteristicsthat affect longevity is a problem that plaguesall such studies lt confbunds

52

activity itself to longevity' lhe analysisof the relationshipo{ the characteristicshave alreadv inlluenced ;". abisolated a nuke or an -;;J-tiJ;" .i.i"" .i *,iti,y That this was not a report in 1967by ,''*iion ot ru"tii"'. study was shown by the physjquesand n. ftl. Ofi"-, .t Ct"u, Sritain, who studied conductorand jobs ofttus f.""i" oi Uf.oa tu" of t"cruits for the the iob itseff could n". i.iuer it f-"nA.n sefore the activity of that British men ,f]."t tft" rn"n.'U" *n"luded: "It is apparent choo'e or are cho:ento *"rr" phlsicalchafacleristic\ "itlnandad'ledlhal i...t. t^ iti""^ * "ppo'ed to conducror' one characren'lrc\' iJ.rudl 'supp.rn'rhe vre\^lhal inherired Io hearrdi\ea5cma) Predispo\e oi*r,,.r' t"it"."...pribilir) particularoccupation" to a -dis inherited or other self-selectionof actjvity by virtue of cltect\ srudie\.relalinfan! type ol 0,"."it,'", J"*".tt"'c' r(crearionalro heatrhand longe!ir! i.iiii'. "r "'.**t.*' erdmple ha\c lesscor_ na fu,tt"rsnt maralhonlunners lol indi\rdurl'qho dre nol o! ."un f*rn a""^. rft'n the lalhers nave Since those who chooseto mn marathons non_ do than discase -u.uthone.s. lessinherited {amily history of coronary men less this alreadv makes thos€ 42-kilometer ;;;h.".'.. nnd mortality evenif tbey nevereven frone to co.onuryais"ase ran to catch a bus, area of blood choles iimiia, setf'setectionoperatesin the for example'thal run terol levels. Although reports indicate' tftoie'rerol lerelsfor srdiovasculdrheclrh f"""trUfV "ff*t' I un rnJiviJual\who ","g ii:.ir,o,ru" ir,ut.,.n telore lhe! beginro cholesterollevels to t"""4" a,Ir"tfs alreadyhavebetter People with certaln pre"lt."t" ii^t tfto". rvfto choose not to run crrqualiliesseleclcertainacli\ilie\ dnd

*' donirknoowhv lt 's the'cpr(e\isring lead t"1.n*,hanthe activitvthatthevscemio

"-ir,i"*.n"*".t',Ot ,in""tn

ii.'iti?,,

"i^.i"i"it"".., to, that may be beneficial --

tn frytofs

em1962study of American railroad_industry 5.i

I TI I E EXER C I S E M Y I 'H

ployees,other problems.fiected the validity of his conclusions. Lower death rates in more active people turned up only in workersof certain agegroups.Frorinstance.only amongsixty, to sixtylbur-year olds were overall deathsmore commonin the most inactivethan in moderatelyactiveworkers. For all other age groups, overall death rates were similar. When thc most inactive were comparedwith the most active, ovcrall deaths werc lowcr only among active workers aged llfty-five to litlyninc and sixty to sixty four. For deathsdue solely to coronary hcart diseasc,the least active men had higher mortalily rates comparcdwith moderately active men in age groups forty to forty-four.fifty-liveto lifty nine and si\ty to sirty,four,bur dealh rates were similar for agesforty-five to forty'nine and fifty to fifty-four. And comparingcoronary deathsof the least activc with the most active workers, death rates for the least activc were high€r for agcsfbrty-five to fo y-nine, fifty-five to fit1ynine and sixly 1o sixty-four, but were not different for the agcs of forty to forry-four and lifty to lifty four. Since there is no logicalor biological rcasonfor thesefigures,chanceor somcthing else complctelyunrclated to physicalactivity seemsthc more likely explanation. Furthermore, there are no data 1o indicatethat theserailroad cmployeeswerereallyrepresentativc of the rest of thlr populalion. For all we know, and as laylor himself suggested,thcy may have been a unique group. with many charactcristics not sharedby the rest oI us. Perhapsmosr important,moreotthc scdenlaryworkerslivedin urbancenters, wheredeathratesarc higheranyway,and the most activegroup were apt to livc in small communities,where death rates arc generallylowcr. This alone can invalidatethe conclusionthat the level of physicalactivity causedthe obseNeddifferenccs/n mnrralrr!rdle\ dmongrhc dilfurenlworh(h. In the 1969Hcalth InsurancePlanstndy.datawereobtaincd by tcvicwing the medicalrecordsof 110,000peopleenrolled in

TH E C ASE AC AIN ST

I- ON C i EVITY

the healthplan. Most of thosewho met the criteriafor coronary hcart diseasewere speciallyexaminedand intervicwed'To de' termine the characteristics,including physicalactjvity, of the population,a random 12 percentof the cntire 110'000people ;eceivcda questionnaireduring the three years of the study' but only 83 pcrcentresponded Only 156patientshad a special cxaminationand an interview ard aNwered thc mail survey questionraire.How peopledescribedtheir activity levelswhen probedby an inte iewer didn't correspondwell with what they harl filled out on the mailed form, Iorcing the study'sauthors themselvesto adviseconsiderablecaution in interpretmg the findings.Also, other vaiables, includingcholesterollevelsand psychosocialfactors thnt might have influencedthe risk asso€iated with physicatinactivity, weren t even considered,and theseand other unidentiliedfactorsmight have independently contributedto both inactivity and hea( attacks' The longshorcmenstudy in 1975conspicuouslyignoredthc bias of job self sclection,which the London transpolt workers study had showed to bc so important. Also, becauscit was possiblethat men had recentlychangedjobs du€ to poorhealth. dealhswcre related to the jobs held six months bcfore thcy died. But it seemsmost plausibleto mc that the onsetoi symptoms of coronary hea diseasewould usuallycome more than six months before death So people who may have been very active whe thcir hearl diseascbegan were listed as inacttve when thcy died. The longshoremen'sunion regulationsdivide eachworking hour of the heavy-work group into 55 percent work and '15 percentrcst, and for thc light-work group' 75 percentof each hour is dcvotedto work and only 25 percentto rest While the authorscredit the "repeatedbunts of peak effort" for the lower coronary risk among heavy workers' I find it deliciouslyappealingto credit their longer rest perjods Certainly the study

55

T H E EX E R C IS E M Y TH

failed to considerfactors such as lack of job sarisfaction.less conviviality,evcn the sheerboredomthat sedentarywork mighr haveenlailed. If Dr. Paffenburger'slongshoremenstudy was llawed. so washis later H arvardalumni study.For somereason, thosewho answeredthe questionnairewere considerablyhealthier than alumni who failed to respond. The fact that those who did respondweren't reprcsentativeof Harvard alumni in general was easyto tell: Haryaid keeps recordsof all alumni deaths, and as the years passedit turned out that those who had re, spondedto the survey weren't dying off as fast as lhose who hadn'l. That should teach us a lessonin statistics.If you want to live longer, the numbe$ seem to say, answer a Harvard alumni questionnaire. In d€pendingon questionnaireinformation about physical activity,the study relied on a mail surv€y,a methodrhe Healih InsurancePlan study and others have shown to be unreliable. The questionnaire,anyway,failed to include questionsabout personality,stress,lcvels of blood fal and other factors likely to be importantin coronarydhcaseandoveralllongeviry.Moreover, about one out of five respondentswho claimed to have no heart diseaseactually did have coronary hearr djsease.It seemslogical that thosc who had heart disease,whether they were unawareof it or simply preferrednot to report it, would neverhelesshave lower actjvity levels,eithcr becauseof symptom limitation such as pain, breathlessn€ss or dizziness,or becauseofthosesubtl€and slill-unidentifiedfactorsthat makesick peopledo less-Thes€ Harvard men would have an increased mortality rate due to their prcexistinghea.t disease,but in tlie studyit would be attributed 10 their inactiviry. All this picking away at studiesthat imply that you can tivc longerifyou exercisemight seemtrivial ifall the studiesaround cameto the sameconclusion.But many inv€stigationsshow no

56

THE CASE AG AI NST LO NG EVI TY

differenceat all in death rates of muscled,sinewy,outdoorsy typescomparedwith sedentaryd€sk wofkers There are evcn srudiesdemonsiratingearlier death for more activepeople. A 1970study oI Italian railroad men showedthat neither overall death rate nor coronary heart diseasedeath rate was relar€{tro occupationalphysical activiry''o Another look at United Statesrailroad men indicatedthat death rates from all cdrrer tte.e higher among physically active switchmenthan men in sedentaryoccupationseventhoughthe coronarydeathrate was low€r amongthe more activemen. And what differencesthere were were those you might find by chance alone. A sevencountry study concluded that if levels of physical activity or inactivity were related to corcnary heart disease,it was such a minor associationthat it probably couldn't even be Sixyealslater, an analysisof 172,459Italian railroadworkers alsofound overall deathratesfrom all causeshigh€ramongmen performingheavywork comparedwith moderat€and s€dentary workels.'' Again, sedentarypeople had increas€dmortality from coronaryheart disease,but the heavy-workgroup died sooner of "degenerativeheart disease,"a catchallterm that includes many casesof coronaryhearl disease Dr. John M. Chapmanand his colleaguesfound, in a 1957 studyof 2,252Los Angelescivil serviceemployees,30 percent /ewer new casesoI coronaryheart diseasethan expectedbased on age in a sed€ntarygroup of workers, and 38 percentmol€ casesthan expectedin a heavy-exertiongroup '3 Overall, there were 25 percentmore new casesof coronaryheart diseaseand deathsfrom coronarydiseasein the two highestlevelsofphysical aclivity comparcdwith the two lowest. A 1967analysisof Indian railwayworkersin the BritishHeat Jou al reported th^t " an unexpected and extraordinary finding in our datais that mortalityin the sedeotaryoccupationofclerks

57

tl

' I HE

EXERC I S E

this is lower than the physicallyactiveoccuPationo{ ntrcrs is contrary to the current conceptionsof the protectiverole of exercise."rlHeavier levelsof physicalactivity conlerredno evident protection or bcn€fit; the higher levels of activity were with the greatesldeath rates. associated study in 1976comparingseverallevelsof In a Scanalinavian for mendoing activityofFinnishmen. total mortalitywas 'i8'eJr heart disease Coronary activity.ls physical th€ most vigorous physical with habitual well mortality dialn't generallycorrelate men' The exertion,but was clearly highestfor the most active authors,membersofthe FinnishHeart Associatior' offeredihe possibility"that vigorous habitual physical activity which exceedsa ceriain threshold is deleteriousor. at least, does not further reducethe isk oI coronary heart discase No doubt thesestudiescould alsobe picked apart to rcveal usesof statisticsare their flaws.All suchrather unsophisticated thing as why one person a Doweriessto explain so complicated ii." of a heart uttack at nftv, and his neighborlives on to be one hundred. Stualiesthat claim that physicalactivity conters longevityare inevitabl] fautty in design,and just as much contralictory data can be accumulatedby the samemethods Jeremy Morris. who maintained his belief that physical activitv orotected againstcoronary hcart disease,was neverthclessa ' candidman. "The evidenceon thisproblemis quite conllicting he admitted."In severalstudicscoronaryheartdjseasehasbeen found to be associatedwith physical activity/inactivityin the expectealway. In as many, no relationsbipwas demonstratecl' or an equivocalor oppositeone; and why this is so is still quit€r There is one simpleexplanationof why the relationshiPbctwecnactivityand longevityisunclcar' Theymay notbc related How much you exerciseand how long you live may not be connectedat all.

58

' rI r F ! A s E A c A r N s r L o \ l f l l

MYTH

*"; lx-lliil'l'i *Hl1::'Ji.'i;,ff1'i1'll",i,iiiJiil'1'li ,,,"l' rr !ou pcniculala5sumption ,',;;il;;. ;,' ir l,ourrartwirhno is no there \LrLldenl! mind li"'."in '" .r;n" $irh anopen

l,ili.''l"ll;i'T'i ri:ltj.*l;g:',1':H;::'.';:"ff t'ert\ecn Iclation\hip \amci'"i"-'.^i i.'i n"'' '' or'uurrhc ;li::'Iiifii: ll,lli;:i l' ilJ.l',-:l, ;::'1":ll norelJrionship p'x "?:n::; -rharis lli ,n.'t..rn'",*"" .,'

'in",:-

"'ir' 'r".:t<'en ot rhe"coninrerPriratron in. mosrrea'onahl(

"'i llicting" resullsfrom all the studres'

hrs lil thN murky\ublcct lt Mor' Uniorlunatrl) lillle Iea'on hrd sho*n eirherno protec i.:. i."i." i**i, "..'kef srud!

j:l*,ii]".i::iJill':i* tl:fi.'i:l':; iiril:l,n:';:x erlecr protecrtve ;" Ihos( rlling to e'rabri'ha ;;;;;;;; couldnr do ln*rn'tr'i"g rhe) in all likeliho'rd ii?.,.i,.. r' $idelv acthe nrorecri!ecrlcctol e\erc'\e t""."., ;;;, rallsun

i#;

"' "

proor i.,;;n;' ta(r'andthehurdcnor

to\ho$ purporr '*I;Jili-:,Llll liiiLl" ""9':' rhat

:llJ,I'i}"".1'i1:i"$:il;: :{:li:lijnru;;,;::fi he Poodrhe er ;;;.""rche mLr'rsomchow ;;;,il-';* di'ea\e sincccoronan l,ll*'i.',i'.^ n*' " oll-baclnosition untirit is undundrasno\cr ;'uarrvunr(r'| ;:I,;:;';';;;";. cannotreallvundoit onceri $ p"tn^otexercisc *it'"*"..J'

r!ui*t*:ii*r :::rxit$t: i[',il::i:-';J;': rmp( u, in a lest ottio'rt t'ur ncverlhele$ the wa) that ercrcisedid iomethinPto *t' *U'. i.t "-"t't

59

,I' H E

E XE R C IS E M Y TH

fats pile up in our arteries,or to the way our artedesrespond to damage,or to an'thing els€we know contributesto €oronary artery disease,we might then still have a treatmentwe should resp€ctand recomm€nd.

TheInsideEviderrce

Exerciseenthusiastsmay well object to having their claimsto longevitydispelledby attackson numbersand methods,and by manner Slalislic' Lludiesdone in lhe citingconlladrclory 'dme to handlc.What aretricky, andhard enoughfor epidemiologists on lhrng'Ihal leaJ(o heartlroublc' aboullhe effcclsot exercise physical evidence, the actual hearts and and what aboul the arteriesof thosewho exerciscand those who don't? Scientistsand researchershave sometimestried to look at exerciseas it might affect the heart at different stagesn the developmentof cardiovasculardisease.There is a certainlogic to this. for it could be that exercisemight have different effects on your cardiovascularsystemat different times in your lifc Perhapsif startedearly enolgh, some peoplereason,vigoroLrs activity could prevent or forestall the developmentof atherosclerosis.the accumulationof fatty deposirsin the arteries Others say t})at if such "primary prevention" does not occur, then exercisinqafter colonarv diseasehas dev€lopedmight provide

60

61

l HE I NSI DE EVI DENCE T H E tX E R ( IS E M Y TH

''secondaryprevention" by slowingup rhc progressof the diseaseand minimizingits consequcnces. Somecardiovascularresearchersfurther rcline that thcsis, and consider secondary preventronto be prcvention ar the stageof eaily vasculardisease,bcfore there are any symptomsorsignsofit, and..tertiary preventjon"to be prevention aftcr there is cljnicalevidcnceof disease.suchas anginapectorisor a heart altack. As tar asprimary preventiongocs,there is no goodeviden€e that relatesphysicalactivity or thc lack of it in early life to the deveiopmentof coronary atherosclcrosis.Autopsiesof young Americansoldierskilled in the Korean and Vietnam wars have shown a surpdsinglyand disquietinglyhigh incidenceof early atherosclerosis. Yer surely mosr soldiels, rested,trained and for€edby circumstance to maintainstrenuouslevclsofexertion. arephysicallyactiveyouths.Judgingby arteriesalonc.however, there was no clue that such a life had any inhibiting effect on the early stagesof coronarydiseas€_ Going back even further, to activitylcvelsduring childhood,Dr. c. R. Osborn, a Brilish pathologistal the University of Sheffietd.has studjedrhe coronary arteriesofinfants and young childrenkilled by traumatic and other noncardiaccauses.lAfter years of painstakingand meticulouswork on the arteriesof over 1,000subjects(some adult), Dr. Osborn has identified microscopicinjuries ro rhe artery walls in infancy that he believcs to be thc origins of atheroscleroticdisease-Theseinjuries have nothing to do with the levelsof physicalactivity of infants and chitdren. r Anoth€r way, perhaps,of looking al possibleprimary prevention of atherosclerosis by exercis€is to look at the effects of lack of€xercise.Can onc at leastguessthat there are benefits liom activity by showingthat inactivity leadsto coronaryheart disease?There is perhaps a hint that inactiviry is related 10 coronary athcrosclerosis.But by all indications,you must be truly sedentary a slug who sits or lies about all day. or barety

crawlsliom bcd to breakfast.to car and desi(and back againlo be at any risk from inactivity. No one who has 1o pllsh a vacuumcleaner,play ball with the childrcn or keep the lawn mow€dis that inactive. Sincethe evidencefor preveotingthe carly stagesot coronary heart diseaseby exercisingis virtually nonexistent,what about secondaryand tertiary prevention? Can exerciseslow once it hasstartedor predown the progressof atherosclerosis vent more heart attacksonce you have had one? Can exercise preventthe arrhythmiathat causesthe suddcncardiacdeathof pcoplewith coronary hea diseasc? program\dr( Theseare crucialque\lionsbccau\eeyercise becomingwid€ly usedin treatingcardiacpatienh. Cardiac"rehabilitation" is the new buzzwordin cardiology.Patientswho havehad heart attacksare being €nrolled at an ever increasing ratein exerciseprogramson the assumptionthat theywill avoid rcpcatedheartattacks,or if they do havc anotherattack,it will be lesssev€re.The very word "rehabilitation" impliesrepair of the heart, and peoplewho pay moneyfor suchpromisesat least cxpectnot to be killed straight off by their direase Suchpromis€scan't be kept. The physicalconditionofheart and arteriesat any stageof diseasedoesn't improve with exand best-controlledstudiesshow crcise.Even the best-designed noreductioninfrequencyor severityof heartattacks,no slowing of the diseaseprocessand no protectionfrom suddendeath. A 1975reportfrom Swedencovered315heartattackpatients who were randomlyassignedeither to an exercisetrainingpro gram or to no program.zThere was no evident influenceof exerciseon €ither the death rate or the rate of recurrenthcart A 1981Canadianmulticcnter study included733 men who survivedan initial heart attack.r After years of follow-up on matchingindividualsrandomly assignedto either a high inten-

63

62

tl

F7 T H E E XE R C IS E MY TH

sity or a low'intensityexcrciscprogram, there was found to he no significantdifferencein eithcr the rate of subsequentheart attacksor th€ deathrate betweenthe high-intensityand|he lowintensitygroups.In actualfact, whereas9.5 percentof the highintensitygroup had repeat hearl attacks,only 7.3 percentof thoselessactivedid. A five-yearWorld Health Organizationstudy of 375 survi vors of a heart attack who were randomly assignedto a "comprehensiveintervention group" or to a control group showed that total mortality was not sign'ficantlydifferent for the inlervention group than for the control group.l Coronarymortalily wasreducedin thc jnterventiongroup largelybecauseof fewer sudden dcaths in the first six months after the heart attack. Since thcsc patienls received more protective cardiovascular medicationsthan patients in the control grcupt thc reduction in mortality speaksonly for the benefitsof a comprehensive treatmcntprogram, not for €xercisealone. Incidentally,there were morc nonfatal recurrent heart attacksin the intervention group than in the control group, and rescarcherscouldn't find any differencein €ilh€r group'scapacityto do physicalwork. An ambitiousstudy. the National Excrciscand Heart Dis' easePrcjcct, was plannedin th€ United Stalesa f€w yearsago of the thcrapeuticeffectsof ex' to make a definite assessment erciseby following a very large group of patients.rAlthough the sizeofthe originallyproposedpatientsamplewaseventually scaleddown, 651 patients who had survived an initial hea attack werc randomly assignedto exerciseor to no exercise, and followed over a three-yearperiod. The results,simplyput, showedno significantdifferencein the late of recurtenceor death. These studiesare admittedly imperfect. Their desiSn,like that of other such studies,can be faulted and the number of subjectsanalyzedis rather small. About 27 percentof patients

61

,I'H E

IN SID E EVID EN C E

areexcludedfrom exercisetrajningprogramsaftera heartattack for other medical reasons.such as heart failure, uncontrolled hypertensionor arrhythmias.Patientsdrop out of treatment groupsunpredictably!and probably som€patientswho are not in the exerciseptogram exercis€anyway.Despitetheir limitations, however, they are the best studies available, and th€ conclusionis that they show no secondarypreveninescapable tion at the early stagesof disease,no t€rtiary preventionafter symptomsare obvious-in fact, no benefitsfrom exerciseat all. When the claimsof primary, s€condaryand tertiary protection againstcoronary heart diseaseare dismissed,there is still a traditionaland widely held view that exerciseincreasesthe coronary collateral circulation. Collateral blood vesselsarc sup' plementarychannelsthat provide connectionsamongthe main arteriesand their branchesand result in an increasein blood flow. Coronarycollateralsconnectbtanchesof eachmajor coronary artery to other branchesof the same anery, and tlley provideconnectionsamongbranchesofthe different majorcorsystemis ofgreat importance onaryarteries.This supplementary blood to the heart musclewhen the a flow of keeping up in narrowedortotallyclosed becom€ major corcnaryarterieshave off by fatty deposits.I hav€ seenpatientswhoseoriginal major coronary arteries were completely obstructedby atheroscle_ rosis. yet whose blood flow through their heart muscl€ was nearly normal due to their collateralcirculationnetwork. The fire interweavingcollateral channelsmay be so extenslvethat the heart looks like it is coveredwith spider webs. For years exerciseadvocateshave suggestedthal exercise promotesthe developmentofcoronary collateralblood vessels. The major supportfor this idea has come frcm an experiment carried out by Dr. Richard W. Eckstein at Western Reserve University Schoolof Medicine in 195?.uThis experiment on

T IIE E XE R C I SE M Y TII

TI I E ] NSI DE EVI DENCE

dogs, not humans involved a highly arificial set of circumstances.Blood vesselswere cul and tied to simulate the obstruction and reduced blood flow in atherosclerosis.Tubcs. reservoirsof fluid and measuringdevic€swere introducedinto the alteredartedesor connectedto the circulatorysystem.The dataindicated,accordingto Dr. Eckstein.thar arterialnarrowing resuksin collateraldevelopmcntproportionalro the degrec of narrcwing-that much of his interprctationhasbeenverified repeatedlybystudiesofanimals and humansunderlessarrificial conditions,and is now well accept€d*and, second,that exerciseleadsto greaterblood flow. This latter conolusionhas not only notbeen confirmcd, but an impressiveamountofscientific evidencecontradictsit. ln an important study of whether cxcrcisc would increase coronarycollaterul blood flow, Dr. Andre Nolewajka and his colleaguesat the Univenity of WesternOnrario. Canada.stud ied 20 patients following a heart attack.r Randomly assigning 10 of the subjectsto an exerciseprogram and 10 to a control nonexercisegroup, and usinghighly sophisticatedtechniquesto measurehow muchblood flowed throughthc heartmuscle,they showcdthat both groupshad similar extent and progressionof coronaryartery disease,and that neithergroup showedchanges in the network ofcollateral blood vesselsor thc amountofblood flowing through the heart muscle. The rescarchersconcluded that exercisedoes not affect the progressionof coronaryartery disease,the amount of blood flow to thc heart muscleor rhe d€velopmentof collateml blood vessels.Anothcr study of\he ettects of exercisetraining, on 16 men with coronary artery disease,reported in the ,4nerican Joumal of CadioloSl, showed that it fail€d to have a significanteffect on heart muscleblood flow.3 Angiographic studies (films of dye injecrions inro the coronaryarteries)by still other researchenhave not shownany increasein corcnary blood flow in either trained athletesor as

hcart r rcsult of exercisein ordinary people or patientswith tIal The consensusof cxperts is that there is no evidence in circulation excrcisetraining incrcas;sthe coronarycollateral to humans.When collateral circulation improvcs subsequent is solely rraining,it appearsto be cojncidenceThe improvement artetres coronary the bo;v's responseto increasinglynarrowed paprogresses,and happeN with or without thlj as the d-isease new ior iient so much as lifting a linger' The only stimulus drscase; coronary is scvere srowthofcollalcral coronaryarteries old your for is it" onrv *uy to grow new coronary channels onesto get worse, i'n l im' lI Drev(nliondoe\nI wor{. rno corondt)crrculalion highly ro lhe nuhrelreat adrocatc.can still rrJ'..r. indirectly "',.*". your health iicizedposition that exercisecar benelit diseasein by cutting down on factorsthat put you at risk for nomen_ the first place. Scientists,agdin resortingto technical jnto and'\econdary" "p mary" ctature,categorizerisk factors and inde_ ones.eimai'y risk factorsare thos€ with a clear-cut ot pendentstatistjcalrclationshipto the development colonary one of the artery disease.In other words, thc presenceo{ afly heart orimarv risk factorsleadsto the occurence of coronary could coincidence rt.qt"n,ry than mere chanceor li."".J."* (Dyper cxolain. Primary risk fnctors are high blood pressure tcnsion). high blood cholesterollevet (hypercholesterolenra) andcradrellcsmoling. Euctr nt ttrc primary risk faclors has been shown unequrv' artery dis ocally to be relaterlto ihe developmentof coronary the average ease.Your chancesofgetting the diseaseate above levelsol high you trave if t+o/90' ifvou, utnoa pre"",rrels over blood the higher The o. lf vou smoke cigarettes you morc the "hot""t".ot pressure,th€ higher the cholesterollevel and

T H E E XE R C IS E MY TH

1 'H E IN SID E EVID EN C E

ii:u:iril:il.:ffiT.,r,lt J:,#1i.,.":; ill:l.il!i:":

hearrdieease. bur arsorhelaresynergisric. i.Jll:9j,:::":]r I nerrenecrs aremorerhanjusraddirive. n. ii.l .r j.*r.opi"g coronary

drsease il )ou smokea lot. for exampte. mayberwrce if lou havehlpeneneon. ::1. Li.":".-"k.1, ql1^pre. Andif y;;r brood roo,rhensk! chores,eror rever 1'11.:::,L"_i rs._atso roo hrgh.your risl of gerring coronary di\ease ma' be rime\ rhatof a personuirh none of rhese "-*" nsk ;::l: .i,\ fdcrorsare rhosewirh a muchresscerrain "-,s::""d,j? alro tesstn.Jependent relationshipto cor

J,;;#i:i:i,j:.J,:::,Jl:l l::i:T^ll.:l l.:,i.,".t;":.:'

socroeconomtc \tatus and. mo\t impoflturt lor rtrepurpo.esor pnr)".^r inacriviry.Mo(r physrcjans :-"1.1:l::'.,": *" rerarinsheaIl di\ea\ero primary acceprrhe risk facror\, :^"]"1:T^ ,har ha\ beendonehassholn rhe \ame llj.,li".i]l -.1":t ""or \rarrsttcat retattonship bet$eenthe development ot coronal) rhe presence of one or more *l TT.:i-1 mcrors, I nesttuatronregarijingrhesecondary of rhe\erisk nsklactor\is less

hearrh arerarre.s crear. rhe ll1,ll. j3lll.lllI.",. oncardiac ..u

rherefore oren ershred.._ ranked :.::11.1.'ii:"].1 "re imponance _b) ph'\,oansandresearch. :..Til^:,.i1_01.,1,

ililT:

ina.i;iriarmos'| urwav' ranks l:: fininhlsrcar

*"", *:"red our rharphysicat inadrvir.) doe\nor .-::':Li::,: precede -necelsarrty_ rhe tormarion of iarrt oo"rrucrron. in thc ,]."9res havenot roundph)\icatinacri\ it] ro lllrl]; 1r]1..,"I a[. Foreyampre. Dr ial H. Rosenman, a (::,:":::j^'":l:ill a rofira carcriotogist. srLrdied 2.6J5tederar emptoyees., He

fromphysic.rr inacri\,ry. whenDr. L. :_:li"-l:"1:. l* ra||nermsen. -:?5weden. ot analyzed several ne lound Inat rnacrivepeopleotren

68

risk lactorstogelher, happenro he those\rho

court dangerby being overweightand/or smoking too much.'o Stayingput may be arrociat?dwith hea disease,but it doesr't makeit responsible.The smokingand eatingpeople do as they sit may be more directly relatedto heart diseasethan the sitting rtself. The most encouragingview of the risk-factorthesisis that, becauseboth primary and secondaryrisks are largely under our €ontrol, we should be able to avoid hea aftacksby avoiding someof the risks that ar€ statisticallyrelated to heart disease. In recent years some studieshave shown that lowering blood pressure,reducingblood cholesterollevelsand eliminatingcig areltesmokingalllead to fewer coronaryattacksand lessdcadly ones.Dr. JeremiahStamler,of NorthwesternUniversily Medical School,suggeststhal we can thank the antismokingcampaignfor 50 percentof the decreasein cardiovascularmortality in the United Statesin the last 15 or 20 years,the move away from high-cholesterolfoods and other waysof reducingcholesterol for 25 percent and better control of high blood prcssure for another25 percent.rrNevertheless,there is less agreement that a person can be assuredof fewer and mildcr coronary attacksby controlling risk factorsthan there is consensusthat the risk factors, when they are present,predisposea personto sufferingcoronary events. When it comesto exerciseasa meansofreducing risk factors. lhere is less agreementstill. For h€re the data are even less convincing.The thesisthat exercisefavorably alters th.r major coronary heart diseaserisk factorsis tar ftom proven. Studics hav€shownconllictingresults,and the interpr€tationof the data variesamong observen. Nonetheless,the thesishas many proponents,and it is sufficientreasonfor many to havc jumped on the exercisebandwagon,if not to have joined the crusade. Since the thesisis less strident and less dramatic than th€ belief that exercisedirectly prolongs life or enhancescardio-

69

t THE EXERC I S F :

M YTH

vascularhcalth, it is perhapseasier to subscribeto this risk factorargumcnt.The claimsthat excrcisemodifiesheartdisense risk factors arc more modest than thc claims that exercisedi rectlyprolongslife and preventscoronaryattacks.And you can believein the risk-factorexercisetheory without the senseol' in accepting ofreason lhat se€msnecessary fervor or suspension The risk-factor thesisis and promoting more dramaticclaims. a morc tentative notion, claimjngonly beneficialalterationin certainbiologicalvaiabtes that. indirectly, may lead to longer life and better health.As such,it is €asierfor exerciseadvocatcs to acceptand defend. But its acceptanceand defensecan lcad to the samemischiefand dangersas belief in the dircci. magical and lif€-enhancingpropertiesof exerciseHigh blood pressureis a major risk factor for coronaryhcart diseasc(as well as for strokesand kidney failure). Dcpcnding on thc criteriaselectedto defineelevatedblood pressurc-and on thispointamongphysicians therc is still somedisagreement it is cstimatedthat 30 million to 60 million Americanshave hypertension.Therefore,major public healtheffortshavc been undertakento find hypertensjvepeople and to get them into under therapyhas treatment.The percentagcof hypertensives risensignificantly,and therapeulicimprovementsin hjgh blood pressureare amongthe majormedicaladvancesof rccentyears. In spiteof pragmaticadvances,we don't know what Nually causeshype(ension. Epid€miologicalstudiessuggestthat it is. for somepeople, related to high salt diets and to obesity, but whcn att€mptsto treat hjgh blood pressureby diet alone are made, the p€rcentagehelpedis discouraginglysmall. Sincewe don't €ven know the mechanismsby which hypertensiondevelops,prescribingexerciseas a way of halting or reversingthe diseaseis no more than a wild guess.Studiesseemto bear out thc sholin{he'dark nature of exerciseas a treatmentfor hy pcrtension.Although some studiesshow small reductionsin

70

I'H E IN SID E EVID EN C I

in trcating hyperten blood pressurcthrough alynamiccxercise cxpensnole sion.the improvementis minor at best Moteover' peoplewith hypertcnthat thc long-tcrm effectsof exercisein ln a studv or s0 caution and tbev advise .';; ;;. '";""*". c' Vod(l' ot Runncrs .o".*,i,i'. .f,.'rn.. Iunncrs Dr'lance ol cleraleLl Incidcncc oorimatHeatrn. rtrerc$rs a substan(ial oi fon\ percenrhad lc\ring hloo'l Pr("ur( . il;J;';-." Ji'ecr'r or rh( .t"n",i irn*,, \'hich l;d D' Harold Llricl to suggeslthal I-ongevitv' ro' op,i*^l Itealth and rouJ"J. people from protect not p;ysical activity Aulfy, "ig-.* 'loes --"p".ft"n" or the whole questionof exp.rspeclive ,n" t'"" by Dru .""". .f t"aucing blood pressureis offercd York "" New at ",.i." U"*it ft4.""t, Clinical Pro{cssorol Mcdicine Committec CftaitmanoftheJoint Nntional U.ai."f C.ff"g. of High Blood Pres-a on Oct"ctinn,-Euat"atiunand Treatmenl can be rccomsure.rrDr. Moser saysthat controllcd exercise reduction and weight i.p."". i,.ess and 1<'aid.in ;;;;J; iipo"ritry, to ieduce blood pressureir a small percentageof Llalrlhal 'r'oatienls. Bul, he \a)'. lh(re rre no con!incing l ro 4 lrmesa lemrri. ererci.., e\cn il p(rlormedvigorouJy of blood lowering continuous *i"r,, rt* t*tl .a ; "ig;ificant 'I he DreDondcrance ol m(JicJlc\ iLl(nceJnJ \en(rmenllhu' In hloodp'c* seem'ro bi rhurclinrcall!\ignihcdnrreductrons evcn when pertormed sure are not achievcdthrough exercise $irh Oirig""trt Ther( mJ}]bc a icw inLlit'ducl' ,Jno,.".rt pres ""1 qhom hlood succe:srul pie'suretnr .irori an exerose pro_ ",i'"'..tnr*a through sure managementcan be achicved prcssuremay not cven be n.ot-.oni.ottlng to.tt mildly high _n"ce..ary vast ma ac"ordiog to reccnt cvidence-but for the .r typertensivepeoplc in this country and i.*" and ineffeclive ',..t'.i "firt" -ni.* simply is inadeqLrate tft" *".fa, "t.t.is;

71

T H E EX E R C IS E MY TH

lr

as a primary meansof treatment, To the extent that elevated blood prcssureis a primary risk factor for developingheart dis€ase,exercisedo€sn'tbelp. Whereasthe sheernumberso{ hypertensivepeopleand the relative €as€of detectingthem make elevatedblood pressure of perhapsprime importanceas a coronary risk factor, it is in tlle control of lipids (fats)-parricularly cholesteroland lriglyc erides that exerciseis reportedto haveits greatesteffect.The exact mechanismby which thesefatty substancesin th€ body lead to atherosclerosis is still uncertain.All we really know so far is that following some sort of injury to the inner lining of the artery walls, fats enter the wall of the artery, becom€incorporatedinto the cellsof the artery wall and eventuallylead to thickeningof the wall and narrowingof the artery channel throughwhich blood flows. When the arteriesare so narrowed, corcnaryheart diseaseis the result. Cholesteroland triglyceridesdo not travel freely as fats in the bloodstream,becausethey don't dissolvein the blood. Instead,tiey ar€ attachedto certainproteins;the combinedmoleculesof fats and prcteins are called"lipoproteins." Ther€ are many different lipoproteins, and they vary in their density or weight.Therearelow-densitylipoproteins(called"LDL"),verylow-densitylipoproteins(called "VLDL") and high-densityIipoproteins (called "HDL"). The far in th€ verylow-density lipoproteinsis largely triglyceride,whereasthe low-densit) lipoproteinsalrdthe high-densitylipoproteinscontainmostlycholestercl, Much attention has been focused in recent years on the differencesbetweenthe various lipoproteinsas they affect the processof atherosclerosis.Researchhas suggested,but not proved,that the low-densitylipoproteinsand the verylow-density lipoproteinsdeliver cholesteroland triglycerideto and deposit them in the artery wals, while the high-densitylipoFoteins removc the fats from the a ery walls. If this evenruallyproves

72

THE I NSI DE EVI DENCE

to be so, low-densitylipoproteinscould be the major villains that contnbute to atherosclercsis,while high-densitylipoproteinsmight tend to diminishthe build-up ol obstructions Some physicians,basedon the work done so {ar, alreadyview LDL and VLDL as 'bad" lipoproteins and HDL as "good " The clinical support for this belief rests on observations that peoplewith more HDL tend to havelesscorcnaryheartdisease, ;hile those with more LDL and VLDL tend to have more coronarydisease.It is imaginedthat HDL could be actingas a chemical scavenger,picking up cholesterol from the walls of the blood vesselsand transporting it to sites in the body where it is destroyedand excreted Whereassomesdentistsconsiderthe absolutelevel ot HDl-cholesterol to be of most imponancein determining whether atherosclerosiswill develop, other researchersbelieve that the ratio of HDl-cholesterol to LDLcholesterolis, in fact, mote significant. Exerciseis claimedby someto increaseyour level of HDL' If the thesisthat high-densitylipoproteinsare goodis valid, then anythingthat would raisethe level of HDL shouldbe of value' Unfortunately,the evidencethat high-densitylipoproteinsprotect against colonary or other vascular diseare is not overwhelrning, nor has it been definitely shown that exerch€ increas€s amountsof HDL. When high-densitylipoprotein-cholesterollevels arc very low. the incidenc€ of corcnary diseaseseemsto be high When the HDl-cholesterol level is somewhathigher,the incidenc€of coronary diseaseis lower' But beyond a certain level-and not a high one at that-the protective effect of HDL seemsto disappear,and the risk of coronary diseaseseemsto be independentof the level of HDl-cholesterol. [f you have very low iDl-cholestetol levels, then a little more seemsto be better' But if you have even a modestamount, more just doesn'ts€em to help much. I,€t us assumefor the moment, however,that high_density

' T H E E XE RC TSE MY TII

Iipoprotcinsare good substancesthat help to ctear cholesterot trom the walls of our arteriesand thereby contdbrte to a reduction.in the risk of coronary artery cliscase.How strong is the evidencethat exercisesigni{icantiyincreasesHDL levels? Of rhc few studiesthat have shown increascsrn HDL in associationwith €xercis€,those increaseshnve generally been so modestthat soberminds might doubt that they havc biotog, ical significance.In many instances,the increasesin HDL are even less than the erors in th€ methodsof measurement. In some.studies,le.r'elsof very-low-densityand low-clensitylipo, proteins fell as high-densityoncs rose, whereasrn olhers the levelofonly one, or neither.ofrhcse lipid_containing molecutcs c]langed.In yet other studies,where, insteadof measuringrhe Iipoproteins,cholesteroland triglyceridelevclsthcmseiveswere measuredj therewereagainno consistent results.And the amount ot exerclsenecessaryto causechangesin the variouslipid levels A number of studiesshow no risc in HDL Ievelsdespite well controlied exerciseprograms.Two hundred twenty{hree heafi atlacksulvivorsin the NationalExerciseandHeart Discase Protecr\^ererdndoml)assigned lo jn exer(iseof nonerercir group, and, atter one year, there were no changesin either SJoupin any of the lipids measurccl.r4 Researchers from Tulsa, Oklahoma,repon€d to thc American Coltegeof SportsMed, , icine that a l2-week walk-jog program thar did have a rraining effecton the cardiovascularsystcmof middle,agedmen did not changeany of their lipids.,sModeratelytrainedrunnersstudied in Columbia, Missouri,L6 and highly trained young men studred in.SanJose,California,,rsimilarly showedno systematicor sig_ nificant changesin fats or lipoproteins. Commenting on rhe surprisinglyhigh total cholesterollevcls and low HDL levets in highly conditionedrunnershe studied, Dr. Harold Elrick said vigorous physical activity ,,docs not . . . guaranteetow rotal cholesterolor high HDl-cholesterol valu€s.. . .,,rsFinally, an

THE I NSI DE EVI DEN CE

importantcontrolled study of 25 m€n and 23 women from ihe Univ€rsityof PittsburghSchool of Medicine showedthat, despite an exerciseprogram that increasedfitness,HDl--choleslerol levels decrcasedin the exercisers.re When measurementslike ih€se are so variable and inconshtent.one would certainly have to be a true believerto claim that any sensecould be made of them. But looking at someof in th€ context of thos€who were measured, the measurements one can find a gleam of sens€. In a study of 81 healthy sedentarymen randomly assigned 1orunning or sedentarycontrol groups,researchennoted that thosewho choseto run mor€, and actuallydid raisethei HDL rhe most, startedoff with high€r HDL levels.,0Studiesof HDL people levelsin exercisersmay well be biasedby self-selection: who chooseto exerciseoften havehigherlevelsofHDL to start Despitethat gleam of sense,the whole subjectof the relationship between exerciseand lipoprotein levels remains obscure. W€re better light to illuminate the relationship,there would still be the taxing question of whether elevatingHDL levelsis helpful anlway. An editorial in the 1982 New Engknd lournal of Medicine notesthat no one has shown that raising HDl-cholesterol reduc€sthe dsk of atheroscl€rosis.':L A report to the International Congresson Lipoproteins and Atherosclerosisin Switzerland show€da 67 percentdecreasein coronaryeventsasHDL levels /ell in r€sponseto a new medication.And it is notable that patientswith a rare diseasein which they have no HDL at all don't show early signsof coronary h€art disease.All in all, it seemsclear that a high level of HDLS isn't necessarilya harbingerof good thingsto come, a low leveldoesn\ automatically meantrouble and efforts to changethe HDL level by exercise are by and large pointless. ln observingan initial group of 260 men for 25 years,Anc€l

75

T'

ll THE I NSI D E EVI DENCE T H E E XE R C IS E MY TH

Keys, of the University of Minnesota, notes no differencetn HDL levels among those who died of coronary heart diseasr and those who survived. Keys concludesthat the current en thusiasmfor HDL is "unwaranted," and that low HDL'cho lesterolis not a significantrisk factor for death from coronarl disease.z The third maior coronary risk factor-cigar€fte smokinghas no direct relationshipwith exercise,but its indir€ct rcla_ tionship is an impo(ant one. The incidenceof smokingis less among runners and exercisers,who can play a set of tennls while puffing away, or have the wind after two packsa day to jogfourmiles? More to the point, peoplewhochoosetoexercise regularly arc often characterizedby their commitment to a whole lifestylepackagethat may well lead to befter health.The same motivationthat mistakenlydrives them to push for ever faster speedsand greater endurancecorectly leads them to avord cigarettesand pay closerattention to nutrition Even Dr' Bass ler, whoseoriginal Marathon Hypothesisis largely responsible for the misguidednotion of runnen' immunity to atherosclerosis,todaycrrdilsrhe hleslyleol lhe runnertor thc supposetl benefitsenjoyed by marathoners. While doctors and scientistsare glad to have statisticalrelationshipsbetween risk factors and coronary diseasefor guid' , ance, they would be happier still to understand the exact mechanismsof atherosclerosisand the minute physiologrcalevents that precedethe cutting off of blood supplyto the heart muscle Were the medicalprofessionto have a completepicture of the diseaseprocess,perhapsdown to th€ biochemicallevel, then interventionat even some very early stagemight be possible. lndeed, that picture is beginningto be sketchedout. Hemostasis,the biochemicalsystemof checksand balanceswhelebythe consisrency ot btoodi\ conlrolled.hasa loLlo do $ilh lhe minute

arteries' and (lctrils of how blood behaveswithin tbe coronary

:lill':J::1.':,:i:"#il'i;:il ti,:,::"lmi:;.:::"ff ha\ d bcncficidlclfecron hemoqtasis li"'rn"t,nr, "',..'* circum\tancc\'hluod is a ttuid Ihal flow' t tn.icrordrnarr \hould an Inlury occurrllloughrhevein' anLlafleric\' Bul cl.i\ ' or an inlcrn"l iniury -lhe sameblood co'! t.r erlmDle. ( hroo'r- bruodcror-i'

:iJ;;;;,"-.;;;;;

floq oasurateLr

' atc conrrolle'l tn*t *cc"ary changc'in hlood ij*.''.o 't" called he' compljcatedbiochcmicalsystem ',"".t * major 'nin",ti";.-;ilo.,gt' """.."".ft not usuallv consideredamons the can system f"f. fu"to.t' alterationsin the hemostatrc rn coronary and ",rr-u.V .ol" in uu"culardiseasein general iuu" u ".ot.ut diseasein Particular' An injury to a blood i..r, f,!to*uti" tyttem is complicated like lalltngdom i" ."'ltl" tnemicdlreacrion\lhar' r**i1." lormeJ' i" *oucnce unlil a clul torms Oncc ,ra. \t\rem al' 'i... "f*. roi'u" nn acrireantrclotrine .i."'u.

lhere is ".inl,''" Ait,of't' (lot: oncclhcyha\elormcLl *,*.r *orf<. lhe hetween qilhin bodv your goingon , Jo"'i"n, cbeminternal 'n,..pru1 svstensvarious tr".a.i.iiJg ""a -ti'lotting to activateyourclottingsystem tend t"i*Jrn."ft'"n;."f "tituli and if not for vour anticlottingcbemistrv' ;., ;;';i;; in manyareasof yourbody' to coagulate *.tra ".*it"i ""o rhdrmanvneoplesirh va'culardiscase '*t;;;.. sLigEest\ bloodclots clotringoJ rr""i r"l^"gg"t'"',.att"denc)tu Iotm impo anteventm liooain tlt"1'o*nu'y u eriesis a singularly neartatlacksA clot ustlallvoccursin an ,i" .^i..,rv "i-":- p-tl"n of the coronatyartery'andis super,*.JJ plaqu€in the artervwall. Manv .t'.n"-dlipid #t..ii." "t.'..*"a held " blood\rream .rii.it- *tpo'tt "t tanou5cell\lrurn'he called fibfin are ralge ;'; i',t.*.,i' ot proreinslrands alwavsthe case' enoughto be easilyvisible'but this isn't 77

76

T H E EX ER C IS E M Y TH

In someinstanceswh€re heart attackshavc occured, yet no clot can be found, tjny clots called "micro-thrcmbi" are the likely culprits.Invisibl€to the nak€dey€, they alsotend to have becomedissolvedby the time a researchercan checkfor their presence. Micro-lhrombj are composedlargelyofplatelets,cells trav€lingin the bloodstreamthat are responsiblefor plugging up injuriesto blood vesselwalls.Plateletsnot orly act asphysical plugsbutalsoreleasechemicalsthattriggerthe processoflatger clot formation.Although you may be awareof such"response to injury" goingson only when you scrapeyour knee or stub your toe, plateleis,blood vesselwalls, clotting factorsand thc anticlottingsystemsall interact with one anolher in a dynamic and ongoingprocesswithin your body all the time. It beginsto look as though atherosclerosis r€pr€sentsjust sucha responseto injury. The inner lining of arteriescan be injured by many things, including chemicalsubstances suchas lal moleculestraveling in the blood, body hormoneslike adrenalineand other natural ch€mical substancesin the body. Outsidechemicalslike nicotine and carbon monoxideare also potentiallyinju ous. (It's int€resting,in this regard,that urban joggersmay have blood levels of carbon monoxideequivalent to thoseof chronic smokers,but they get theirs from sucking traffic-pollutedair into their panting lungs.) The artery lining may also be injured by mechanicalforcesl suchas the shearforcesof the blood itself. Both risesand falls in shearforceagainstthe wall ofthe arteryhavebeenimpljcated. Sometimesthe simple trauma of blood cells bumping against the inner lining of the blood vesselmay produceinjury. These traumatizedcells may then releasechemicalsthat further the clamage, Any injury to the inner lining of an artery causesplatelets to stick to the site of the injury. There, the plateletsrel€ase moleculcsthat stimulatecellsdeeperin the artery wall to multiply and to migrate to the inner su aceof the artery, causing 78

THE I NSI DE EVI DENCE

it to thick€n. Cholesteroland other tipids canied in the bloodstreamare then depositedin this thickened' injured area As this process injury to the artery lining' stickingof platelets, thickeningof the lining and depositingof fats-occuN repeatedly, the channel in the artery for blood flow is progressively narrowed.Finally, plateletsnot only stick to the iniurcd inner surfaceof the artery, but they form clumps,which releasestill otberchemicalsthat lead to the massof coagulatedblood called a clot. At this point, if not earlier, when plat€letshave formed onl) microrhrombi.d hean anact'i\ likel\' Someclaim that exerciseaffectsthe hemostatrcprocessDy tilting th€ balanceawayfrom clofting and toward the dissolving of clots,a changethat could be viewcd asfavorable'at leastby potentialvictims of coronary artery disease lf the claim were hrmly supportedby scientificevidence'it could be a reasonable pants The iustificationfor jurnping into sneakersand sweat evidence.however. is far from convincingand even suggests that exercisemay som€timestilt hemostasislhe other way' toward clotting rather than anticlotting ln one sturly, clumping together of plateletsstimulatedby in a \mall numberot e\erci'rngmen hut' decreascd adrenaline in spiteof the fact that only the exerciseaspectof the Program was well publicized,their rcgimen also includeddietary modification and abstinencefiom smoking, so b€nelitscan't fairly The authorsofthe studyth€m be attributedto excrcisealone.'13 selvescommentedlhat the biologicalsignificanceof what they observedwas unclear. In other studi€s,platelet clumping r'credJ€dafter exercise.a And so it goes.The thi y-five or forty studiespublishedin majorjoumalson the effectsofexercisealoneon plateletclump_ ing-one of the big stepsin forming clots-have found variable resulls:sometoundan incrrdse.\ome a dccrea'ednJ othcrsno effect at all. The degree to which the platel€tstend to clump may be

79

r-i

T IIE EX ER CIS E MY l ' H

uncertainjbut thc absolutenumbersof plateletsdo go up willr exercise.Almost all studiesof platelet numberfollowing slrcn uous excrciseshow ircr€ascs in the plateler counl, the aclull numberof plarelctsin the blood. Dr. H S. S. Sarajas,ofFIcl sinki, Finland, found that plateletsincreaseto asmuch as twicc their baselinenumberafter both shorl-term(30 minute)runnjng and long-term (maratlrcn) running and protonged brisk marchcs.z. Platelet-clumpingactivityatsoincreases. If rhestudiesrhatshow increasedclumpingafter excrciseare accurate,and there is an absoluterise in platelet numbers,and thoselarSernumbersof clumping platelets also induce more activc clotting, exercise beginsto look downright dangerousfrom a hcmostaticpoinr of However,it is the iffinessof all this work on hemostasisthat standsoutmoreclearlyrhananyconclusionswhenall thestudies arc examined.Two more examplesconvincinglyshowthat there sinply isn'l much to be said one way or the other about the effectsof exerciseon conrrol of blood consistency.In a 1g8l stuclyon blood viscosity,or thickness,researchersat Cornell Universityand Columbia tjniversity fbund rhat sedentarypeople have very slightly rhicker blood (about 4 percenl) at resl than do trained runnen.16Thicker blood doesn'tflow so easily, and it is known that pooled blood-blood that isn,t Uowingat all*tends to clot. But after cxerciserunnershad increasesof 5 percentand nonrunnersincrcasesof4 percenr.leavlnga mere 3 percent differencein blood thicknessbeLwccnrunncrs and nonrunnersas groups, ln a secondexampleof baffling results,scientistsat Duke Univenity reported that phlsical onditioning enhanceclrhe body,s ability to dissolveblood clots under rhe artificial circumstance of having a tourniquet around the arm; th€y aiso found, but didn't emphasize,rhat und€r ordinary resting conditionsrhe ability to dissolveclots apparentlydecreased.,T If an exercise-

u

THE I NSI DE EVI DENCE

prcducedincreasein clot-dissolvingability is a benefit' then the ,.1"".""." ut .".t after people have exercisedmust be a disadvrntase.Sincemoslol us-e!en exercisers-spendmoretime ut resithan we do with a toumiquet aroundour arm, the results uren'tencoumgingfor exercisersWith the interplayof clotting 8nd anticlottingactivity going on in us at all times, anything' exerciseincludcd.that diminishesour anticlottingfbrcesseems ro presenta potential fisk. Exercisershave expectedthat their intuitive senseof gaining vigor from a good sessionof handball or 20 laps in the poot wouldactuallyshow up through the measuringrnstrumenisand under the microscopesof sci€nce There .trould be real phys_ iologicalchanges,not only in staminaand brawn' but alsodeep inside,at the very heart ofthe matter. This gift sciencehasbeen unableto give them. The whole scientificcommunity,cardiol_ ogistslike myselfespecially,would lik€ to ptomisethat exercise removesthe fatty obstructionsfrcm artery walls' reducesthe pressureof blood againstthem, keepsthe juices flowing But we can't. There simply is no evidenc€to support thosehopes or protection from its As fai as prevention of atherosclerosis is concemed,exercisewill get you Ilowhere' consequences Therc is still another promise,widely offered and so powerful that it compelssome people to run when they want to walk, to pushaheadwhen they long to rest,evento drive themselvesbeyondthe common limits of pain and exha'rstion That promiseis that physicalexertion leadsto psychological,emotional and spiritual benefitsas well as physicalones. Physicalfitnesscan make you feel better. But doesit sooth the nerv€sand cure depression?Does it lead to grcater self: Is there a magicalunion oI body, mind and soul? awareness? Can you run in a spiritually usefulquest?

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Exercisehas been creditedwith a wide variety ofpsychological bencfits,from plain old "fcelin' good" to euphoriathat verges on the mystical. Since thcse effectsare inhercntly subjective they defy easymeasurement,How do you measLrre me amouni of "good" a pcrson feels?And when you can-psychobgical testingdoesseemto measuresomething you can't sayfor sure where the goodnesshas come from. Ncvertheless,the simplegood feelingthat comcswirh a ljttle' sweatis so w€ll known to most of us as to be unarguable.I fcel good after a s€t of tennis, and my beer tastesbetter after an afternoonwalk on the beach. Maybe pulling weedsdoes that for you, or maybc it takes a two-mile run. Whatever kind or amountof effort it takes,working for a while a little clos€rto your physicalcapacityusuallybrings a certainpleasure. Bul even this lowestlevel of emotionalbenefitisn't universal.Therc are thosewho abhor a drop ofperspirationand clon.t feel the leastcomfort in being pushedto exercise.Their degree of pleasuredoesn'tparallel their bodies'oxygenconsumption;

cxcrcisefor them is a "downer." They may get the samecomfortableand pleasantfeelingsotheft gct from exerciseby reading a good book or craftily checkmatingan opponentin thc cool of a chessclub. rccesses There's nothing wrong with the cxperienceof those who hateto exercisc,and there s nothing inherendyright about the experienceof those who love to. Simple experience.lbr each of us, simply is what it is. To assumethat all peoplc will get pleasurefrom what pleasesyou is as foolish as assumingyour childrenwill eat their spinachbecauscyou happento love it Your delight and their dislasteare equally valid, and equally unarguaDre. claimtherupeuticben Atthe ncxt level,however,exercis€rs efits,suchasrelieffrom anxietyand dcpressionHcretheprom isesbecomcquestionablc,and the necd for objectivestandards becomesmoreevident.lfa personin cmotionaldistressis misled by baselcsspromises.that is a cruclty that shouldbe stopPed; if the bcnefitsare real, exerciseis a most aPpealingtherapy The idea that Physicalexerciscconfers a variety of thera_ peutic benefits is ncither new nor outlandish. A number of experimcntsand studicscarriedout over the pasl severalyears improvementsin intellectual, havereportedexercis€-associated emotional and social areas,especiallyin people judged to bc suffcring psychologicaldistress. And the subpopulationsof chronicallyanxiousor depresscdpeople .re a maJor mentalhealth problem. Most investigationhas concentratedon thc questionof whctherphysicalcxercisemight alleviatedepression and anxiety. Psychologicaltcsting has established uresof thesesubjectivestates.There are problems,though,in evaluatingsuch studies and drawing conclusionsthat can be appliedacrossthe board to the populationin general. First. therc is disagreementon what constitutesa psychologicallyhealthy individual. lhe day rnay come when w€ can biochemicallyassessthe

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hugevariety of hormonesand brain iransmittermoleculesthal ultimately control our subjeclivefeelings.analyzetheir inter actionsand comeup with an objeclivemeasureofjusthowgood or bad a person feels. That day is still beyond the horizon Meanwhile, research€rsand therapistsmust rely on what arc called"subjectivetests," which, by elicitingaperson'srcactions to neutralstimuli, suchas blandpictur€sor meaningless shapes, or by analyzinga penon's responsesin hypotheticalsituations. allow the testerto gaugehow cheerfullyor gloomily, with whal calmness orfear, a perconviewslife. How well thesetestsmatch how the personperceiveshimselffeeling and whether they accurately predict what a therapist will find during the deeper pfobing of treatmentare unce ain, Besidestestsfor nnxiety and depression,there are alsoselfreporting techniquesfor gaugingsuch related aspectsas selfesteemand socialoutgoingness.The resultsof the two sortsof t€stsgenerallyjibe well: a personwho is judged depressedby subjectivetestingreportsevidenceof low self-esteemand clinpoor apical symptomsof depression,such as sleeplessn€ss, petite and fatigue. In a way, this correspondence betweenvarioustest results crcatesprcblemsin evaluatingthe effect of any singletype of trcatmcnt.If a person'sdepressionlifts after treatment,did the, therapywork dircctly on his depression,or did it work by improving self-esteem,by offcring social support or by helping him to sleepbetter?The problemofinterpretationis particularly difficultwith exercisebccauseit hasprovedimpossibleto isolate excrtionitselffromthemanyothercomponentsof atherapeutic exerqscprogram. Also, although standardizedpsychologicaland psychiat c criteria for anxiety and depressionexist, it's hard to relate our own normal€verydayconcernsto pathologicalstates,The same m€asurableamount of anxiety that pamlyzesone individual

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il miehlleadanothertu gel oul lhereanddo 'omelhrngabout Orieofus rnightbe immobilizedby the quantifiablysamedeprcswe sionthat anotherof us coPeswith well lndeed' anxietythat find reatoo others, can identify as arising from a causethat b€ sonable losinga job or havinga desperatelyill child-mav the healthyresponseto emergencythat movesus to handlethe ol situationas best we can, just as depressionafter the death us allows that someonewe love may be the heakhy withdrawal eventuallyto reorganizeour psychesinternally, and to recover' If "free-floating"anxietyfor whichwe canfind no externalcause beyondwhat realitv\eem\ lo e\plaincanbe 'ucor depreision cessfullytreated by any therapy, we have no way or Knowrng whethei the sametreatmentwould work for normal fears and ma) be \adne\s.And perhaps.becau'elhesenormalresponse\ The complexity them treat try to ones,we shouldn't necessary anJ male\ mca'ulementinlerPrelaliun issues ot o\\choloaic.rl Wc .rutuutionu tor lrickierlhan counlingPlatetel' 'houtd re gard "objective" studiesin thesc areaswith some skepticism Almosi all studiesof exerciscas therapy show some cflect in junior-college on depression.A Californiastudyof {:lepression stude;ts in a semester-longjogging courseshowedthat' while both men and women improved their physicallitness as ex_ Dect€d.onlvthewomen, evaluatedby testingasmote depressed ut th. ou,""t, improved their psychologicalfitness' Analyzing the data. the studYauthorsconcludedthat thosein the poorest phleicalanLlp\)chotogi(alcondilional lhe 'tan rmploredlhc ' Thir un\urprrs'ng mosr,borh phy\icxll) and psvchologrcall\ the lower you obviousi the conclusionseemsmerely to restate anLl lhe motc )ou arc. the more room lhere i\ lo move up imDrove,the better you feel about it. The idea that exerciseperhapsalleviatcsdepressionbest in thosemost severelydepressedto beginwith hasb€ensuggested lunners aswell- In agroup o{58 beginning_level bv other stualies

T H E E XE R (]IS E MY TH

who ran for a self-chosennumber of hours ovcr a ten-week period,the mostsignificantimprovemenrin..depressionscores.. wasby the most severelydepresscdsubjects.:Sincethe subjects themselveschosehow much to run! important pcftonality differencescould well havc confoundedresultsattributed purell In another study of universily students,both normal and depressed subjeclsshowedlessd€pressionfollowing a ten-week jogging program. Again, thos€ who jogged the most showed the greatestimprovementand also were the most depressedin the first plac€; they had themselveschosenthe most vigorous exercise.Bccausethe investigatorsdid not concealthat the pur pose of their srudy was ro measurethe effect of exerciseon depression,the authors of the study themselvessuggestthat "the subjecrs'choicesmay reflect their complianc€-or thcir desperation."3 The resultsof any study of psychotogicalvariablestend to tte influencedby the psychologicalmake-upofthe subjectsand their expectations of the ourcomeof the experiment.A subject's pleasurein physical exertion or expectationof benefitsmay enhancehis ability to get better, just as his distastefor exercise or his skepticismabout its benefitscan obviate any therapeutic , effect. Belief that a treatmcnt will help makesit helpful, even if the treatment is a sugarpill or a nonsenseincantation.This lact hasbeenwell known to sciencefor centuries,and hasbecn namedthe "placebo" effecl from rhc Latin for .'I will please." The placeboeffecr is not imagination,but a biologicatphe nomenon; although its mechanismshave not yet becn eluci_ dated, scientistshave little doubt that measurablebiochemical changesarc brought about through the inlangiblesof hope, beliefand the kind minisrrarionsof olhels-with or without rhe addedallurc of a dummy pi . The effect is, in fact, so powerful that these days no tdals of new medicationsare crcdible to

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doctorsunlessthey incorporate "double_blind" methodology, in whichneithersubjectsnor experimentenknow who is getting lhe medicationand who its dummy counterpart.Only in that way can researchersdiscernwhether a new drug has an eftect beyondthe placeboeffect. Double-blindstudiesofth€ effectsofexerciseon depression arenl possible-there is no "fake" versionol exercise,or any wayfor eitherexperimentersorsubjectsto be blindloit. Therefore, every study done is tajnred by the placeboeffect, and so is the subjectiveexperienceof normal people who dose their ills with exercise. lf you're repeatedlytold by friends. family, professionals andthe mediathat exercisewill uplift you and provideemotional "highs," belief rnay be sufficientto mak€ it happen lt is quite possiblethat antidepressanteffects following therapcutic exerciseprogramsare largely due to the expressedand implied hopesof the expe menters, as well as to the expectationsof th€irsubjects.Indeed,in onestudyofex€rciseaspsychotherapy for depression,the therapistweighted the scalesblatantly by joggingwith his patients. Fu hermore,if you're told that a cours€of actionwill have a certain rcsult, and you invest time. energy and money in carrying it out, you are not easily disposedto admitting that you did not achievethe result. You may even feel foolish and have a naggingsensethat you might be lackingin somethingif you don't feel what others do. Few arc ready to admit, either publicly among their acquaintancesor privately on some psychologist'sself-repoft form, that perhap'sthey should have bought a book inst€adof sneakels. When people are openly unenthusiasticabout physicalexertion and when their skcpticismabout its benefitsis high, exercisedoesn'twork so well. In one analysisof an exercisestudy! for example,the dropout rate was very clearly affectedby the

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ii

patients' teelingstoward the exercisesessions.a Those who di(l not have a strong belief in the benefirsof exerciseshowedthe highestdropout rate. -fhe oneswho droppedout soonesrwer. not only the leastenthusiasticabout exercisein the first Dlace. larigueanclpercer\eJlr Ie or no Dsv(ho. bul alsoexperienced logicalbenefil.As rn orherstudie\.lho.c who uereenrtru.rrsrr alsocompliedthe bestwith what experimentersw.ishedof rhen. and they benefitedthe most. The sameholds true for exerciseas jt relatesto anxiety.the other maror psychologicaldiscomfort for which exercisehas been credited with benefits.Expectationsanu p€rcepnonsmediate a person's responseto any given effort. ln one investi gation, the placebo effect was incorporated, though in a differcnl way from double-blindtrials. A number of adult males were to one or threegroups:a standardexercise randoml)assigned prolocolot enduranc€running:the sameererci\eafter swdl lowing a placebopill participantswere told would reducelhe fatigu€and discomfortof exercise;the sam€exercrseatter Der, relaxatione{ercise\aiththe sameassur_ lormingan innocuous it would reduc€ fatigue and discomfort.i After visorous ance thal therei\ u\udllya rransienlincrease exercise. rn anxiert.-When this expectedrise in arx(ietywas measured,rhe usual;esponse wasatrenuatedin the placebo-pillandplacebo_relaxation srouDs rhat rheywouldfeel be er, alrhoushmeasby the e'(pectarion and hormonatresponse\ urcd cardio\ascular lo rhe irandard ex€rcisewere the samefor all groups. A small but very wel-conrro ed study by Dr. Dan EDSrein divided,ubjectsinro those$ ho $ere newlyto pa icipalein an exercisegroup, those who were to partjcipatein a familiar but sedentaryactruty and those who were to take up a similarlv quiet acrivilybur one rhar wa\ new ro rhe parrifrpanrs., The purposeofthis rather elaboratedesignwasto take into account the possiblepsychologicaleffectsof simply slaning a new ac_ 88

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else Although Dr' Epstein tivitv. be it exerciseor something group qould sige\ercise Lhe 'how if,", 'ubjecr' in a\uellasincrea\e' "l"j.,"a and anxier) i" atp'e$ion comparedwilh the orherSIoup'' "il.*ia".*^* *tirtutlron i" i"Jt- u"a r.r, dr.r,-g L\ercisersshowedno signifi(ant iit"i-.,i.;' "* in hodv-1t or increaser 'ellll."r'"i'n u"p."*,o" o' url\ier) groups: all reacted indced other the *ilh t",iu".,i"" "itpr*ano parttculalchangein dn) ot lhe p:)cho+.*,"g .-ifr ", measureo loeical '-"lt variahles reducshowne\ercise-related i.r.u. ..,r. sludieshare WashPill\' of Ferris N Dr' nol r,onsin anrrery,orhersh
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immediateshort-term reli€f, does that mean a routjne of e)i ercisecan havean effecton chronicanxietyover the long ternl, Many srudiesof exerciseand alt€rationsin mood involvc relativelyf€w peopleobservedfor mtier brief periorls of timc_ methodologic prohlem\lhar lenderconclusions harLlto aDnl\ lo rhe mullituderhdrhastakenup erercrsea\ a wa\ ot lite. tn a nudy b) the NalionalE),erci.eand Hean Disedseproiecl thcseproblemswer( eliminaledb] usinga largesamnle anJ sruoyrngthe \ubJecbu\era Iongperiodoflime.The srudv\ a\ also!aludblein rhal ir adLlre\seJ ilrett to psychosociat h;atrh in general,inctudingdepression,anxiety,hysteria,nervousness and sexualactivity. The study group was651 male survivon of ah€artattack,andthesesubjectswereevaluatedbeforeexercise and at 6 months, 1 year and 2 yearsafter exercrsebesan..lhe resulrs.publi\hed in rhe Archivesol Int"rnat Medkrn; in IgB2. were clear: "This study indicaresthar volunrcers. . . ln an ex_ erciseprogram for a two year period do not achievegreater psychosocialbenefitthan do contrcl sLrbiects.,l Sincerhereare contradictoryclaimsofpsychologicalbenefit _ IIom exerctse,we needsomep€rspective.we are probablvwise ro concedelhdt \ome peopleqho lr' e\(rcisca. d rhera;) tor oepre\\ion or anyret'are helped.allhoughtharis a far cr lrom ! rheidealhaterercrseie psychotugica y uptiftrngtor a . Curitre pornt ls not so much whether exerciseworks, but, rather, that it has no specialproperty to recommendit_ The mixed results of studies,in fact. seemto indicatethar cxercls€a eds mood an-dpsychologicalstat€ by meansthat have nothing to do spe_ cificallywith the physiotogicalelTectsofexertion. The important and unanswered quenionis: Wouldn.ranlrhingetseorherthan a program of jogging, aerobic dancingor other workouts ac_ complishas much? Whenpeoplehaveenteredexercisestudies,iheyhavealmost ahrdysent(reda ,ocialsituation.They ma) haucbssn,,16..,,

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a who now run together, patients who now join togetherin therapeuticenterprisc.The meresocialinteraction-ihe baorcr by and;attcr amongsubjects,the concemfor thei welfbeing thc €xchangcof opinionsand progress-musl the researchers, is the enemyof the depressedand me Isolation the spirits. lift anxious.Give suchpeoplea group to belongto and fellowswm whom to unburdenwordes, and somerelief is bound to occur' Suchreliefalso comes,however,by singingwitha churchchoir' or by goingfishingwith "the boys," or by doing volunteerwork in one's community. Exercise,if enjoyed within a group, bas of someconviviality,but it hasno monopolyon the advantages Socialaspectswere rated highly in a surveyof factorsintiuencingresp;nsesto supcrvisedexcrciseplograms ln an interestingstudy in Public Health Repo t, Dr. F ed Heinzelmarn and ii.trard w. Bagley examinedsuch factors' At the begin' ning of the prograris, desire to feel better and healthierand the con;ernsabout reducingthe chancesof a heart attackwele primary motivationsfor peopleto join. The socialaspectswere ;areLtas lea.timporlanl.In conlrasl.r sune! ot lhr pallicipanls ar Ihe cnd ol rhc c\rrci'e programsindicaledthal Lhe'oclal aspectswere among the best-likedfeaturesand an important reasonfor peoPlechoosingto stay in th€ programs A senseof mastery thc completionof a task, the accomplishmentof a fcat or the learning of a valued skill that once seemeddifficult or impossible-may also explainsomesalutary reeffectsof exercisc.Suchfeelingsof masteryarc commonly ported asphysicalfitnesslcadsto greaterphysicalperformaoce Moreover,as exercisersbecomemorc fit they are likely to vlew vut themselves albeit incorrectly, as we have seen-as less are nerable to hcart diseascand death Just as people who depress€dfecl all sons of achesand pains, those who bclieve themselvesto be in the pink of h€alth feel che€red l wouldn'1

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for the world put down strong backs and nimble feet as an avenueto feeling emotionally strong and flexible as well, but this way isn't everyone'sway. Why not the masteryof a degrec in socialwork, the nimble fingersof a knitter and the stufijv back of th€ trout fisherman? There are as many ways to feel at the peak of one's powers as there ate people. Exercis€ may also simply be a diversion, a time-out from worries and responsibility.How deeply can you worry about your work wh€n you're wo.ried about getting your next breath? Can you think quite as much about the kids when you're not sure you'll ever get over the next hill? Diversionarytime_our ftom ordinary concens, not exercisespecifcally, is credited with psychological benefits by researchen who have found simple quret rest, vigorous exerciseand meditation all equallv effective i0 reducing aoKiery. You ll heartbe samehom sramocolleaorr. potlers and weekendcarpent€rs.

1

While social intemction, mastery aDd simple diversion may explain many of the reported psychological benefits of physical activity, the very recent discovery of intriguing changesin body chemistry accompanying vigorous exertion has refocused attetrtion on the physiologyofexercise.Until late in the last decade. what little we knew about subjectiveemotionalstates.such as fearor aggressiveness, wasthoughtto be mediatedby hormones you or I read about some time ago in high-schooltextbooks_ adrenaline,testosteroneand so on, These hormones,which circulate freely iD tlle blood, have very general effects and act on organs and tissuestlroughout the body_ How they might be r€latedto responses more subtlethant}rereddenedfaceofaneer or lhe palpitalionsot panic. to rhe pleasuresot nostalgia.ior example,orthe stimulationof discussion-rcmarneoa mv$erv, t-ackingan obvious bridge betweenlhe finer poinrs of menral Iile and grossphysicalma0ifeslaltoDs,ir remainedacceprable

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to distinguishbetween"mind" and "body " Mind was something that transcendedphysiologyor biochemistry' and was thereforenot subject to the quantitativemethodsof science, whos€provincewas the body Beginningin the 1970s,researchersisolateda whole ncw group of substances,which they soon realizedmight mediate all sorts of activity among nerve cells in the brain' including thosethat control pleasureor the lack of it, clarity of thought of mood or unnervingfluctuation.Mind or confusion.steadiness and body thus began to come together-we are our biochemistry in spiit as well as in the flesh. Among the first and most fascinatingof these neurotlansmittersto be discoveredwere the endorphins,opjatelike moleculesproduced within the brain that have effectssimilar to morDhineon the centralnervoussystem Although little of the data accumulatedso far havebeen €onfirmed,endorphinshave beencreditedwith shuttingoffawarenessof pain in peoplewho have been grievouslywounded, have been linled to the pain relief of acupunctuleand, somesuspect,may explainthefeeling ofwell-beingthat typifiessomeplaceboeffects Needlesstosay, whenit wasdiscovercdthat blood levelsof endorphinsrisewith exercise,there seemedat Iast to be a mechanismby which exerlioncouldcausepleasule.it nol euphoria The fact thatendorphinlevelsin the blooddse with exercise, however.doesn't demonstratethat they are the causeof any changein emotional siate. Dr. Peter Farrell, of the University of Wisconsin,emphasizesthat emotional effectsof exercise'if there are any, occur in the brain, but the human data on enl' dorphinsdeal with levels in the bloodslream w€ just don't know whetherthe level ofcirculating neurotransmittersrellects rhe le\el wirhinlhe hrain.Aleo. to respondto neurolransmiliers, brajn cellsmust be equippedwith the proper receptor,to which the transmittermoleculecan attach-Peoplevary consid-

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erably in both the quantitiesof endorphinsthey manufacture and lhe population of receptorsthat will acceprthem. And. {inally,people'sability to producemore endorphinsin response to the stressof exercisealso varies_ Dr. William P. Morgan,ofthe SportspsychologyLaboratory at the Universityof Wisconsin,saysthar there is suchtremen dousvadabiljty in endorphinlcvelsamongdifferent individuals both before and after they exerciselhat it is hard to see rhat neurotransmitteras the caus€of a specificc€ntralnervoussystem et}ect.,, As a 1980 r€view of the subject stated, littl€ is known abour the physiologicfunctionsof endorphinsand rheir clinicalimplicationsare not well understood_,, Perhapsmost relling is a recent study reported from the Universityof Hawaii.,rA group ofmarathonersunderwentpsychologicaltesting before and after running for a minimum of one hour. They were given an injection of eilher a plac€boor a drug known to block the effectsof endorphins.There were no differencesin thc mood changesassociatcdwith running. The drug and the placebo acted similarty, indicating thar al_ thoughmood changesassociared with runningmay be real, rhqy are not mediatedby endorphins. Nevcrtheless,the discovery of endorphinshas lent some credibilityto the ultimate expressionof ex€rcise-induced akerations in psychologicalstates-the euphoria thar has becomc known as the "runner's high." We do know that morphine,so similar in structure to an endorphin that it fits inio the same receptor,may produce euphoria in at least the early stag€sof addiction.And runners as well as some other dedicaledexer_ clsersotten ascribe their perseveranceto an addiction to the high they get when they push themsclvesto their very timir. One cannot dismissout of hand what has capturedthe imagi_ nation of so many. Dr. Morgan and other rhoughtfulscientists are not convincedthat a runner.shigb ev€n cxists, but obj€c_

I

of what MD magazinecalled tivity palesbeforethemagicalvista "Unitv with nature."r" lhe exneri(ncelhi\ wa!: J,'. ceorecst'.ettantta\described roa'ldnd hadheen ''I r*J lr., ,it*t.A o ronghill on rhe river fe(lingof whole' the it happencd log t t'en ,"a"..i t. n 'f." meI loved nyself over ;()rltentmentcame o"""" ""; in il I had no longer to will what "".. ""4 una """.vthing "nJti.-JJa ro be runninsmc lwasina ;;": ;"';s The load seemed ro leave Dlaceand timeI never$anteo ' and runner fiom Aus Dr. John Deaton' a physician'writer tftat one of the most desirableaspectsof ti.,-f.""r, "....nt" !ou againtrndagainIo lhc hn *oo;nn '-:: . i. tfra il canlr
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pistol and "the few secondsbetweenthe rcpo of the starter's are rich, and within the final thrust across the finish line to explore The worlds new 6nd them the sprinter will always at hand the the momenl Oer.eprions .t arp.n ana focus in on ro bleak begins lii ai'ui,ionr",*..n."nsciousness and in\tinct clarity ancl down, and the flesh responds to the vrill with a qhatever 'b For il s $orlh' Drecisionmost ot us rarely know nol a\ time of sPan same iunner Evelyn Ashtord describesthal as a but a "sharpening,""focusing"' "clarity" or "prccision,'' "senseof unrealness"2r such hvObjectively speaking-which is hard in the face of or any jumpers, climbe6 Derbol;-very few runners' dancers, omnip' of sense .ut. u"hiev€ euphoria The lina ot "*"rJ""r. of total relaxation and "Z€nlike" peace' invincibility, otence and have o{ either sharpened perception or dreamlike states that tew very the been described will elude all but phys_ we don't understandwhat a "runner's high" is' what e\erche whether ioloqical proc€ssesmight bring il on oI even know: il i. ini onit *uv to aJieu. it But one thing u'/edo ht the erercise is a pathway to euphoria, the reward is bought exoenseof extremesof exertion punishment The belieflhat the rewardofa highsurpasseslhe yourselJevei reouired to attain it meansthat you must push the limits traiJer, Ueyonatfre uundaries of everydayrisk and ol sympawareness of orudence.Il demandsrhat you suspend plumbelief toris, of *urning signatsot faligue and Pain l he mets you toward danger.

TheDongers of Exercise only.alillle morebizarre someof lhe dangersof exerciseare in the re80Peachtree lire Runners ;;',;;; ;i ,#',; """vda'

*- *. Ii:**I"ililll'!iil::';'l:l'i*L; *nll"*rtii.'.""i"g year'oter 100hadheen aunnga single and 'i"'*r.-" cansbolrlesrce liquids "".rLi., inclujing ii "oi."i. havebeenkilledbvtalling ; people *urse' ot l'. Jr" ,".*. blame cant necessarilv lij*"i "i*i,r. it*a* p'rreoivstil!:vou lreakacodent:and l'"i.ii i., ."*o*; aoss flvinsrocks tt-Jii,llt"lin". one-thirdof thoserunnerssu{fered n"to' hadlo "ver ot runningalone'andmatbe'ftey ii,"rtit""tnt rhat Thekindsof iniuries *"ti . -t*i thatchance ii "'i;,,L

T'il#$?liiH'T: :i*itr#x*:*."..:"*:ffi

i ll

T H E E XE R C IS E MY TH

I

possibilities.In one extensivesurveyof recordsof 1,650amateul runnerswith 1,819injuries seenin just two yearsby two phy siciansat the University of British Columbia, in Vancouver. doctorsD. B. Clement and J. E. Taunton identified 19 types of injuries to the knee, 22 to the foot, 13 to the lower leg, 5 tr) the upper leg, 8 to the hip and 4 to the lower back, as well a\ a numberof additionalpainful injuries to eachareathat werenr diagnosedmore specifically.z Injuriesin other sportsand variouskindsofexerciseare also common.A random surveyof squashplayersfrcm two squash percentinjury mte over their clubs,for example,found a 214.5 yearsofplaying (which averagedtwo yearsin one club and eighl in t}le other), meaningthat just under halfof all squashplayers are injured while playing.3About 10 percentwere orthopedic. includingback injuries,torn ligamentsand tendons,sprainsand inflafinnation; the remainder included la€erationsand ey€wounds. Contrary to popular belief, tlle better and more experi€nced playen in this study had mor€ seriousand disablinginjuries. Perhapsthey play harder and take more risks-so much for amateursportsbeing "all in fun." The problems of tennis players are well known-"tennis elbow," shoulder,knee and leg injuries. Most are caus€dby the abrupt stops,turns and twists our joints are ill-designedto withstand, not to mention t]le pulls and strains that occul when fancy maneuven don't come off well. In an attempt to patch t}le damageand carry on, straps,bracesand bandagesare now probablycommonerthan white shins and shortson the tennis

THE DANG ERS O F EXERCI SE

Skihg injuries are so commonthey're part and parc€lof the sport. A collegecampusafter winter vacationoften looks like an orthopedic clinic. And many an executive wears his plaster as a badgeof honor. Orthopedic surgeonslove snow as much as ski-resorloDeratorsdo,

Dr. JamesNicholas,onhopedicspecialistinNew York City, cstimatesthat 17 million to 20 million sports injuries are reported each year, and that perhapsanother 10 million go unreported.4Dr. Kenneth Cooper, who put "aerobics" up there with Mom and apple pie, estimates that 60 to 70 percent of all runnersare hurt badly enougheach year to cut back or stop their programscompletely.5Surveysand studiesof runnercshow injuries running-€xcuse the pun-from 60 to 90 p€rcent Runninginjuries are especiallycommonbecauseof the punishing force your body has to take. The imPact on each jogging stepis two to three times your body weight. On average'your feet will strike the ground 800 to 1,000 times per mile. If you are a 150-poundrunner, you genente and must endureat least 120 tons of force p€r mile. lf you run two to four miles every day, you fac€ frolr,i' 7m 6 1,920 tons of force each week A marathonermay easily face more than 3,000 tons in a single lace, Exposedto such stress,it's no wonder that muscularand skeletalinjuries happenso often. Kneesare the most vulnerablepart of a runner'sbody. The PeachtreeRoad Race su ey determined tlat about tr8 percent ofnew injuriesinvolvedthe knees.Dr. David M. Brody, whose George washington University runner's clinic has examined more tlan 4,000 Patients,found that more than one-third of the injudes were to the krce 6 Other large studiesagree.The commonestinjury, known as"lunner's knee," is due to grinding of the kneecapagainstthe bone beneathit lf you could seea knee in motion-muscles contlacting, tendons and ligaments pulled taut, bones and cartilage sliding and grifiding over one another-you would appreciate more easily all that can happen ' It may be a miracle that damagedoesn'thappenmore otten. The lower legs and feet are the next most vulnerable areas DoctorsClementand Tauntonfound 28 perc€ntand 17 percent of injuries involved, rcspectively,the lower leg and the foot,

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with various forms of inflammation and fracture heading thc list. Dr. Brody also reported that lower leg and foot injurics are commonestafter the knees A vafiety of other anatomic sites-thighs and pelvis,for example-lhen follow as lesscom' mon locationsfor running-inducedinjuries. The rccuperative period from such injuries stletchesto weeksand months The disability,both acuteand chronic,is often signilicant-Time lost from work and direct medicalcostsmay be considerableEven a spraincan sidelincyou for weeks; and a compoundfiaclure is going to make you and your doctor long-timebuddies Of €ourse,what conditioningwasgainedfrom exerciseis generallv quickly lost dudng recuPeration Most of these injuries are avoidable.Runners hurt them selvesby running too hard, or too long' or over terrain that is too sleep, hard, rough or uneven for them. Othcr €xercisers, too, get hurt by literally throwing themselvesinto the game' Damageto joints, muscles,tendonsand bonesgenerallyresults from overuse,not from acutetrnuma, suchas, say, a nastyfall are those on an icy pavement.The practicesfhat hurt exercisers do so thcy to think would like One for themselves. choose they or misinformedbecausethey are uninfoimed Lots of people do injut€ themselvesduring strenuousexercisebecaus€they're unaware of just how easily injury can occur. They pick up heavy objects the wrong way, and strain their backmuscles.They launchinto a fast tennisgamewithout warmingup, analtear a stiffmuscleunreadyfor forceful stretching. They go out to jog for the very first time' and an ankle unpreparedfor the poundingof pavement"gives" as they tum a corner, or a tendon pulled for an hour without rest becomes inflamedand painful. Knowing this can h€lp if you're willing to makeallowancesfol the limitationsof bones,joints, muscles and tendons. Whereasit's possiblethat some regularexercise$are truly

100

about what uninformed,and don't s€eor hear or read anything pltnl) ul in the\ do, runnersin narliculdrarc likcl! to ha!c b) dn overridrng iurinarion.Yer .en.rhlerdviccis orerwhelmed your life Dedicated for messageirun haraler'run longer-run protectthem_ thatto runneisreallyadhereto the desperateidea senseof selvesfrom rliseaseand death' to attain the exalted pain and beingfully alive, they must drive themselvcsbeyond exhaustion. to stop Dr. Sheehanboasts that he won't allow his body are his hands €ven though he is "running on empty " When he keeps clawingth; air, his legsteadenand pain is everywhere' H< finJt de'ircs so deLP(ratcl) rhe6ni.h he runnin"ero*ard heroicandhedeemsil theracithe moralequi!alenlol\at of exdepth to alemandof ou$elves incrediblee{fort "beyond "You have to ertion."s A Iamous coach says,less poetically' run until ithurts." And anothertellsme that the real satisfaction then going comesfrom "pushing yourself to your limit-and

I

L

beyondit!" runnen ln the flrce of this so of encouragement)some be€n insimDlvcannotrun sensibly.The term "addiction" has growing number o[ a crei'inelt u,ed to erplainlhe dedicalion oIlhe Morgan acti!iry Dr'Will'amP or ioggiruro punr.tring the Univisity of_Wisconsin'claimstheserunnersdemonstrat€ of realaddrrliun.Tbe) w'll Jo dlmoslan!maiorcharacreristic. thrneto set a funning fi{. and lhe} hd!e wrlhdra$rl-}mpiI lhcy canI romi. ,,,.tt a..t.pt..tion. Irritahrlit)3nd insomnia addiction run. Although less studied' the same symptomsof An exerose have been oiserved among other exercisers,too will ignore he stop; told to when addictwill keep on goingeven exercise' He may it pain and take medicinesor shotsto rcliev€ are "neaFcnpsaysDr. Morgan, to the point where injudes Dline."e only ierhaps the tcrm "exerciseaddict" can be applied to

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a small minority, but a frightening number of exerciseenth(l siastsact contrafy to reasonand commonsens€,as though irr pelled by some demon of their own to disregardthe signrr\ Toronto western Hospitnls iiven by their bodies ln a surveyat sportsmedicineclinic, which is availableto all comers' nearll one-halfof the patientswaited liv€ daysor longer1o seekmerl ical help after being injured.ioThe longestdelayswere found amongthose who set the highestpersonalPerformancestand ards. and who regardedth€ir activity as life-enhancingand heallh promoting. Clinic doctor Geoffrey J Lloyd noted that the in jured tended to minimize the painfulnessof the injury and to disregardserioussymptoms.They didn't perceiveobviousinjury assignificant,dido't want to believ€they were injured and were reluctantto discontinueactivity to allow injuries to heal Even JamesFixx, author of ffte Complete Book of Running ald the lastpersonto discourageit, admitsthat "when a runner comes b see [a physician]with an injury, it's his last resort He will havetried everythingels€he can think of that might enablehim to keep running-including prayer."tl Ofcoune. full'time athleteshavebecomenotonousforcontinuing in the faceof injury. Doug Petersen,the Olympic skier, continuedto ski for three weeks with a fractured vertebra in his necl,ihe nnalll had lo undergosurger) As reponedb' FraserKent, a medicalwriter, he was quoted: "Deep inside, I knew thcre wassomethingwrong, that I wasinjured "rl All too often. such ordealsare viewed as heroism. wone' thesedangerousdenialsbecomein many recreationalathletes'mindsthe model they are to follow Dr. K. Wayne Marshall, of the Universityo{ Toronto, feels lhe pain\ athlelesma! misinlerprel lhat ahhoughrecreational thev experience,they compound ignoranceby "macho" stoicism.H; hasfound that thosewho consistentlyendangerthemselvesby {tenyingthe significanceof pain are also those who

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THE DANG ERS O F E\ ER( I t E

to achievethesegoaLs "had set unlealisticgoals Their striving often ""-en led to iniury'"rl is Jim Ryan' a television reporter and avid "*u.oi" a network TV news runner, who descrited his experiencein run His ff" ft"a t"f, p"in in one thigh after a l0-mile """..*. day After that' he ,lipon"" *". ,o ton 11 miles the following could ''-fn bar€ly walkthe appalling fqlS, ,.f"ti"lo. watcherswere treatcd to from a 6 2-mile view of Presiaent.limmy Carter being forced lallering And lho\e racebr hi. phl.rcian.tho sawhrm !isibly

tharrhe Itr82ma!recall *i" iirr"*iair'" e.".n Mararhon 'n low and dehydration almostdied of

*inn"., ,Cfbe.toSalazar, FredLebow' ioav temoerutur.rigtttafterhisgreatvictorySaid pr"iri""itf dt" N"* vork RoadRunnersClub' "lf that kid or dying'he wouldchoosedeath"r' iala '-- choiceor lo"lng c;nnotclaimto be uninformedor *rt" ""nainiy not immuneto the "rt"ti.i""", of the dange$,are themselves unawa're .o.t,- tenselh'rlleadslo \ucha highinciJence **.".;." "f Neq YorkStdrephv .i J*'J..-,"a*.1 i"r"rie\' A sedentao "[ trainedin a."";t* ft"* ft" tan the BostonMarathon: 60pounds l lost "1.i". that u* f *.tldn't recommend ,"" my toenas -..iftt,{romzeromilesto 20-mileruns i lostall andwent Bloodwasrunningout of my shoes"'r fromwest virginia ,e.non"t*"igh;lodle-aged cardiologist in last-but coming r"acewith a siressfracture' ."" ;;";;. Austin' ena s r u.otf'er doctor,JohnDeaton'from " eventbougn ']oJ. iexas. decidedto nrn anupcomingqua(er-mamthon of his"alldav fifth th€ on flu *""*tr'g fr;m tbe i" "-,::ilr't"* Hc'elfro l05' shor un "".lr.i or"*','i. nistemperature upon wounLl ai"eno..aui"rupt. "r theflu bul tourilay'laler marndantheiospitalcriticallist with lobarpneumonia"The leel at qhal \ ou ser. D ealon \ ays. is lhal t he ec\ t asy ) ou a sir en song lo do t oo i ave acc., m ph. t r edm ay lur e you li|e

103

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much too quickly, to ignor€ the soft whispersof caution that comeirom your body . . . euphoriaand a teeling of indestruc_ tibilit)canoverriLle aches.pains.eren(ommonsense. The hurt comeslater...."'7 If these are the exerciseheroes,then surely exercise€nthusi_ asts-bcginner, novice and expert-ar€ in for trouble. The machismo-tintedlensesthrough which we seesuchfollv rrans_ laressiring uut lhe lav serof lennisor \towinsro a \*aik*tren jogginga\ givingin andgivingup. Nor is drivin!rhehodyharder than it can take confinedto would-bemarathoners.or to men. Slow joggcrs who only want 1()jounce off a few pounds and \uburbanhou\ewrves \rho worrr about sagsan.JLulgeshave joined the injury statisticsin droves. Wom€n. in fact. are Dar_ ticularly prone to their own varietiesof damage. Specialvulnerabitityto o.thopedic injury in women exists mainly becauseof anatomicaldiffer€ncesin rheir bones.ioints . Womenhavea \lighrerbone.tructurf, andmuscles. $ ith more delicateligamentsand tendons.The structureoftheir collasen. lhe marrixol conneclireanJ olher supporring lissue,,is d,ffeF ent. Their center of gravity, the plac€ where the body experi, enc€sthe greatestforce, is betweentheirhipbones,makingthem rulnerable lo pelvicinjunes.$herea\In menthe..nt", oi qrur_ ir! rs usuall'higher.berweenthe chesrand waist Dr D;nnis J. Sullivan,orthopedicsurgeonat th€ Hospital for SpecialSurSeryin New York City, found that five out ofsix stressfractures in the pelviswere in exercisingwomen over rhirty yearsof age, and there have been similar reportsoffrequent stressfractures rn women from other researchers. The wider pelvis ofwomen-great for th€ exerciseof child_ birlh but not for running-means their thigh bonesstandat an angleand lean in toward the knees,causingunequalstresses on the insideand outsideof the knee joints. Their kneesare more

t04

THE DANG ERS O F EXERCI SE

l I {

mobile and their thigh musclesweaker, so their kneesarenl held in plac€so well, making them vulnerableto knee injuries Evenamongtop-rankedt€nnisplayers,manymorefemalesthan malessuffer knee injuries. Women's narrower shoulden and chestsmake them more prone to shoulder dislocationsthan men are. General body flexibility, although an advantagefor dancingand gymnastics, addsto the risks of dislocationand fracture. And there is the additionalelementofinadequatepreparation.The late Dr- John L. Marshall,famed orthopedicsportsmedicinespecialist,suggestedthat the greater number of strains,sprainsand dislocations in women who first start exercisingare due, at least in part, to lessprior training. And Dr. Howard A. Kiernan, or_ thopedicsurgeonat PresbyterianHospital in New York City, found an "epidemic" of knee ailmentsamongioggingsuburban housewives,which he attributed to "poor condjtioning."'e Thereis alsothe disturbingpossibilitythat somethingserious is goingonwithin the bonesoffemale exelcisers.There is recent evid€nce,for example,that women runnercmay losesignificant amountsof minerals, such as calcium, from their bones,and th€rebydevelopearly osteoporosis a condition characterized by lossof bone min€rals,leadingto "softening" of the bones, pain and vuln€rabilityto injury. This prematureloss of bone seemsto be intimately tied to changesin femalehormonefunction inducedby exerciseIt has beenknown for someyean that there aie interaciionsbetween physicalactivity and tlle menstrualcycle. But it is only since womenin greaterlumbers have taken up physicalexercisethat hormonechangeshave been recognizedas a generalproblem. Earlier surveysof women athletessuggestedthat about 10 percent had abnormalmenstrualcycles,More recently,as women have becomemore involved in year_roundtraining programs, the occurrenceof menstrualirreguladtieshas increased.

r05

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It's not clear just how exerciseinducesloss of menstrurl regularityor evenstopsmenstruationaltogether.But it appears that when exercise-induced loss ol weight reduc€sthe fat in rl woman\ body to belowa certainproportion,variablyestirnated to be bctween17 and 22 percentof her total weight, menstrua tion is affected.Women who train the mosl and weighth€ least tend to have few or no menstrualcycles. Whateverth€ mcchanismfor exercise-induced m€nstrualab normality, it seemsclear that those women who stop men struatingdo suff€r from osteoporosis,just as womenleno ro do after menopause,when the hormonebalancetheir bodieshavc b€en accustomedto sirce adolescencechanges.Womcn wirh amenorrhea-lossof menstruation-due to ex€rciseseemto be as much at risk for bone loss as much older women would normallYbe. The consequences of bones lacking in minerals are fairhr The, re paintulandlheybredt moreeasity.Orhe;, predicrable. nonorthop€dic,resultsofhormone changesinducedby exercise arenot well understood.Certainlyfertilityis diminishedin women who lose their periods, althoughthis is an imperfectmeansof birthcontrol, becausesomeathleticwomenwithout Deriodsmav slill ovulateand becomcpregnanr.(tncidentall!,no unusu;l problcmshavebeen noted in pregnantrunners.There is a won_ derful tale that hascirculatedthrough medicaland running circlesof a pregnanrrunn(r $ho didn r feetue onc Jay during a run, discoveredshe was in labor, and ran the remaininqdis_ lancelo lhe hospital.whereshega!e hinh to a heatrhybib1.1 Men and women are equally liable to thermal problems heating or cooling of int€rnal body temperature. the exc€ssive While th€rmal abnormalitiesdon't put you up in plaster or sentenceyou to crutches,they're medicallyalarming_Any exerciserbalancesthe heatgeneratedby aclivity wilh the h€atlost through evaporationof sweal and other m€chanismsof bodv

t06

THE D ANG ERS O F EXERCI SE

hcat loss. A combination of high-intensilyexercise,high air tcmperatureand humidity and body dehydrationcan lead to overheatjng,called"hyperthermia." The clinicalexpressionof hyperthermiacan vary from relatively mild heat crampschaF acterizedby musclespasms,through seriousheat exhaustion, to heatstroke.which is life-threatening.With heatstrokethe person'stemperaturerisesto above 105', his brain is affected' so that he is confused,deliriousor falls into a coma, followed by circulatorycollapseand even death. Needlessto say' unaccompaniedexercisersare at greatrisk;onc€confused,th€yoften can't seekhelp. When the temperaturcand humidity climb into the 9G. exercisers-and that meansbikers and tennisPlayers jnstead. as well as joggers-should probably take a swim The opposit€ end ol the thermal injury spectrumis "hypothermia," body temperaturethat is too low. Overcoolingis just as seriousas overheating.when the weather is cold, and lightly clad exercise6sweatheavilyin a prolongedeffort, their bodytemperaturemay drop markedly.Ifbody temperaturefalls below about 90', irrational behavior, loss of coordinationand contu\ionmayoccur:thc I iclimma!. ho$evet.remainuna\rare of his own symptoms-again a reasonto not exercisealonc ln severecases,respiratoryinsufficiency,cardiac rhlthm irregularities and dangerouslylow blood pressurefollow. H]?othermia, too, can end in death. A few people are even allergic to exercrse,or at least are fellealby the samesyndrome,called"anaphylaxis,"which is the most se ous allergicreactionin thosewho are sensltrveto) say' shellfishor bee stings.Why some people should bring on this suddenlossof blood prcssure,swellingof the throat andinability to breathesimplyby exertingthemselvesis unknown.In a report of 16 patientssufferinglife-threateninganaphylaxis,tlle attacks were precipitatedby jogging, running, playing socceribasketsyndrom€can occur ball or tennis and even by dancing.'?r'The

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THE DANCERS O F EXERCI SE

without any previoushistory or symptomsof allergy,in novice as well as trained athletes,and training does not decreasethe likelihood of it occudng. Another allergic-typereaction is called "exercise-induced asthma." Those with a history of asthma may already be aware that breathingin cold air or exertingthemselvestoo much may bring on this spasm of the lower bronchial tubes. About 2 percent of the general population has such a history, but a lot of other people who have never had classicasthmaare also susceptibleto asthmaprcvokedby exercise.Although anyexertion may precipitat€it, running is the commonest,probablydue to t]le cooling of bronchial air passagesduring rapid breathing. Some researchersbelieve physical exertion itself, even without cooling of the bronchial tubes, may stimulatethe secretionof a spasm-producing substanc€. "Runner's anemia," or "sports anemia," desetvesmention becauseso many people are awate of it, and concerned. It's a reduction in the number of red blood cells and hemoglobin (the protein within red blood cells that carries oxygen) of exercising athletes, Since there doesn't seem to be an'thing wrong with the runner'sability to produce red blood cells or hemoglobin,the more likely explanation is that an excessivenumber of tlle blood cells are destroyed during running. The trauma to the blood cells by feet pounding on the ground is the likeliest explanation, a theory supported by the fascinating caseof a man confined in a mental institution who becameanemic by constantly pounding his foreheadwith his hands. Some researchers,on the other hand, believethe anemiais a physiologicadaptation,which, by diluting the blood, allows it to flow more easily. While runner's anemia is fairly common, it's generally mild, and performance doesn'tseemto be hampered. Exercisersoiten pursue their goals in spite of small nuisances

like snifflesand coughs.Such garden-varietyailments,we are told, will go awayin six dayswith tleatment, and in half adozen dayswithout. Unfortunately, a whole host of viral infections, includingthe common cold and flu, can causean inflammation of the heart muscleknown as "myocarditis," an often serious, smolderingand permanentlydamagingdisease. The person wit]l myocarditis, though sreezing and aching with tlle usual symptomsof mild respiratoryinfection,may be quite unawarethat his heart has been affected.When viruses find tleir way to the heart muscle, they are usually few enough in number and don't make their presenc€ known We do not even know how many people may have had myocarditis with so little effect at the time and so little damage remaining that the diseasehas never been suspected. When a personwith myocarditisexercises,however,viruses in the heart musclemay multiply. As they incieasein number, they causemore inflammationand damageto the heart muscle The more acutethe damage,the more likely is pernanent scarring. And it is now believedthat many casesof otherwiseunexplained chronic heart failure weaknessof the heart muscle and inability to pump blood-are due to earlier episodesof viral myocarditis, perhaps unfelt at the time and many yea.s in the past. Thosewho "work otf" minor viral ailmentsmay be courting a chronicheart conditionin their later years,and evenan acute, sometimesfatal. exacerbationof myocarditisin the present An example is a thirty-one-year-old man who was training for a marathon.A few weeksbeforethe race,he felt tired, developed snimesand mild muscleaches the usualsymptomsof vadous "bugs" we are all susceptibleto. He continuedto run dailyeven when,threedaysbeforethr race.he beganlo experiencenausea and a vaguediscomfot in his chestwhile running. By the day of the marathonhe felt even wolse and had to stop at 16 miles

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becauseof chestdiscomfortand vomiting. He had acute myo carditis. Myocarditis is a happier diagnosisthan som€ other hearl conditions,for many recovercompletely.But to exerciseduring any viral infectionis gamblingon the possibilityofchronic hearr failurein later yearsand, during the acutephaseof the disease, suddendeath thcn and there-right on the racecourse. Most injuries and abnormalitiescommonto avid exercisenare certainly not "just what the doctor ordered," but even myo carditisis at leastrarely fatal. The sameis not necessarilytrue of heart attacks-and they are a real danger.Cardiaccatastto phe, in fact, remainsthe overwh€lminglycritical dangerof exercise.This is so not only becausethe fatality rate is high, but becausetlte risk of cardiaccalastropheis not so easyto avoid as the risk of tendonitis or heatstroke.People with coronary heart disease,even of severedegree, can often comfortably pcrform at lev€lsof vigorousphysicalexertionthat are not safe for them; the waming signalsof impendingdangerare not al, ways dissimilarto innocuousdiscomforts,and so are ignored; and sometimesthere are no warningsto heed. A meeting of cardiologistsa few years ago heard that the first astronautwho ever walked in spaceshowed frightening abnormalitieson his electrocardiogramthat was t€lem€tered back to earth during his extravehicularspacewalk. Since he was superbly fit accordingto extensivepreflight testing, the physiciansat mission-controlheadquartersbelieved that the electrocardiogramwas an aberration due to the strangeconditions in outer space.The astronautperfoimed satisfactorily, feltwell andpassedpostffighttesting,too; the medicaljudgment seemedjustified. Nol long afterward, the astronautdied in a space-capsule fire, and an autopsydisclosedextensivecoronary

n0

THE D ANG ERS O F EXERCI SE

Not only is superbphysicalperformancepossiblein thc presenc€of severecoronaryheart disease,but also the peNon may himselfrot feel symptoms.I know patientsofexceptionallitness who have severecoronary artery disease Even people with canPlay'ports.c\erciseandrun falal heandisease imminenlly They may haveno symptomsandmay be capableoloutstanding physicalperformancewith heartsthat will kill th€m More often, however,ignoringsymptomsand signsthatusu_ ally warn of a seriouscardiacevent contdbutesto the all-toofrequ€ntoccurrenceof catastrophesassociatedwith strenuous ex€rtion. An exerciserfeels shon of breath. weak' unusually tired; he ascribeshis symptomsto a largebreakfast,abad nighfs sleep,an "off day"-or even to "th€ wall," as runnerscall it, that he must break through to get to his effortlessstid€ If his chesthurts. his shoulder,his arm-those arc just the pains of the game. W€re the penon sitting in an armchair his alarm might be immediate,but in the midst of the pound and sweat of exercis€,he expectsdiscomforts More pernicious,ofcourse, he has been led to believe that he should push on past thesc symptoms.And iI he has also credulouslysubscribedto th€ protective effect of vigofous activity, he may clampenapprehensionwith strenuousstolclsm, All such ideas. and Dr. Bassler'sMarathon Hypothesisin particular, raise false and impossibleexpectations And they lill. Any idea that exerciseprotects ftom hea diseaseleads people1o attemptwhat they simply cannotsafelydo. The Marathon Hlpothesis goes further, {or, in ord€r to obtain "immunity," it asksbelieversto undergo the punishingregime of the 26miler. Not only is that itself a terrible burden on a sick heart. but someoneconvincedof his or her lmmuntty to coronary heart diseaseis just the person who would neglect and ignore the warning signsof impendingcardiaccatastrophe. Of cour\e.if the MardlhonHlPolherh \4erelrue lhen a

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marathonercould safelyignore the symplomsand signsthat. in a nonmaralhoner,would suggestcardiac disease.Crazily, n(r one sc€msto recall the full slory for which the marathon is named.In 490 B.c. the runner Pheidippidescarriednewsof thc Greck victory over the Persiansfrom Marathon 1()Athens-a distanceof about 26 rniles. Upon deliv€ring his message,hc dropped dead. Evidencefrom today's marathonersindicatcs fhat droppjngdead-and from a h€art atlackat that-is at leasl ascommonamongth€se"heroes" as it is amongthe rest of us. Doctors Bruce F. Waller and william C. Roberts.of the National Institutesof Heallh, in Bethesda,Maryland,reportedon ,ive patientswho died while running, lwo of whom were marathonersand none of whom had clinical evidenceof cardiac diseasebefore becomingrunners.,, All five, the marathoneN of severecoronary atheroincluded, died from consequences sclcrosis.The findingssuggest,saydoctorsWaller and Rob€rts with polite restraint, that "Bassler'sthesisthat marathonrunis incorect." ning provides'immunity to athercsclerosis' Othershavc coroboratcd that fact oflife. DoctorsTimothy D. Noak€s and Lionel H. Opie, of South Africa, reported autopsyevidenceof coronaryatherosclerosis in four marathoners.zrDr. RenuVirm ani , Chief of thc Divisionof Cardiovascular PathologyResearchin the Departmcnt of CardiovascularPathology of the Armed ForcesInstitule of Pathology.in Wash ington, D.C., reviewedthe autopsy,indingson 7 marathoners who had completed a total of 64 marathons.z4 Four died of coronaryheart disease;their coronary arterieswere found to be severelyaffectedby atherosclerosis. Dr. Virmani then per, sonallystudiedaulopsiesof 3 other marathoners;2of them had died of severecoronary atherosclcrosis.Compa ng all causes of death among marathoncr autopsiesshe reviewed,Dr. Virmani found that sevcrc coronary atherosclerosisis the most commoncauseof death in marathon runners,.5

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Findingsare about the same for less demandingforms oi nrnning,too. Dr.-Virmani, continuingh€r studiesof runningdeathsafter pub_ her initial findingsfrom marathoners'autopsies'revicwed joggen' lishedreportsof deathsof57 runners'4l ofwhomwere Coronarvbeart diseaseoccurredin ?7 percentof the subjects studan
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developeds)-mptomsof coronar) arterydiseaqeattereightyear, or runntng,rrAngograms showed99 percent blockage ot one or tne malor coronaryaneries...Documentationof hjscoronarv artery diseas€. saysDr. Handler. ..and its relationship to hrs lsyrnpromsjareununpeachable . . . thispattenrrematnslhebestdescnbedexampleof the lailure of a vigorousrunningprogram to preventthe progressionof corcnary athetosclerosis,,, Other forms of strenuousexerciseare no bettet at protecting againstheartdisease.In a report of2l athletes,only I of whom wasa jogger. Dr. Lionel Opie touod coronary hea;t diseaseas the causeof death in 18.,, Other studieshave no better news to add. Regularexercisedoesnotpreventthe developmentand Dro_ gressionol t)?ical and se!erecoronaryatherosclerosis. In mosr rnstancesof death related to exercise,in lacr, cotonary ieart diseaseis rhe usual finding. Dr. Thompson. discouraged rhar not even rhorough medicalsurveillancecould singleoul those at risk, summedup the problem. ..Exercisedeathi rlo occur,,, he warned. and rhere is no definite way to idenlity asymptomaticindividualsar risk. Supeflorphysicalfi,n<ssooesnot suar, anlee prolecdonagainsrexercisedealhs.. young may die during exercise.atrhough. ,-E*l lh:.':ri unlikerheirslighdt oldercounterpans. whosedearlsareu.uatty rclatedto underlyingcoronaryheart dis€ase,the causeis mosi often a cardiolascularabnormalir) rhey were bom with. Dr. uarryJ. Maronand his colleagues ar the NationalInslitutes oI Health analyzedthe heartsof 29 competitiveathleteswho had diedberweenthe agesot I.Jand 30 years. Twenty_foul of rhe " re oreddunngexenion.andaUdiedof oneor anolher form of unsuspected hea disease. The commonest cause was hvDer_ tropbic cardiomyopathy.a generally inherited form of iearL muscle diseasecharacterized by unusual enlargement and dis_ organzation of heart muscle cells. There are many torms of

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THE DANcERSoF ExERcISE cardiomyopathyunrelatedto the coronaryarteries,heartvalves or an),thingelse in the heart that might producedamage.Not only is the causeftequently unknown, bur the diseaseis almost asfrequently unsuspected. Evenwhen heart diseaseannouncesitself. denialofwarnins s',rnpromsis a recurrent rheme in man) studiesand repons oi exercisefatalities. Even the simple advice to ,,get more exercise" offered offhandedly by many doctors may be enough to make people ignore the signalsthat should be heeded.In Dr. Thompson'sstudy of jogging-relateddearhs,6 of 13 subjects who died from coronary heai disease had waming symptoms that they ignorcd, and none of thosewhosesymptomsarosefor the first time during jogging reducedtheir level of exertion.rl Derek G. Steward, a former world-classathlete, described his own experience with denying the symptomsof coronary heart disease.32 After a briliiant athleticcareer,he retircd from competitionbut continuedtoexerciseregularly.When he found his exercise,tolerancelower and experiencedchestpain while loggng, ne lnrerpretedthesesymptomsas signsof "unfitness." He wasnot psychologicallyprepared,he says,to acceptth€ fact that he was a candidate for hea disease.Finally, after pain forc€d him to stop after 100 yards of jogging, it beCameimpossibleto deny his true condition. Severecoronary artery diseasedevelopedand progressedin this training athlete althougl he was capable of considerable ph)sical exertion for a lolrg time while his coronary a(eries were closing down. Dr. Bassler,sclaim tiat it is biolosicallv impossiblelor atherosclerosis to progressin anyonecap;le oj even walking the 42-kilometet marathon distance is clearly untrue. Stewald's experiencecontmdicts it, as have doctors Noakes andOpie, who havedocumentedthe progressof coronaryartery diseaseduring th€ life of a marathonerwhile he continuedto

T H E EX ER C IS E MY TH

The evidenceis unassailable.Coronary heart diseasedc velopsand progresses dudng exercisetmining and conditionin! programs.Exercisersdie of heart diseasedespiteexercise.

THE DANG ERS O F EXERCI SE

the sameratio: alnost all of them duringsle€pingor beingmildly active, only one twenty-fourtl of them while exercising vigorously. The data from studiesshockinglyshow otherwis€.Sudden deathwasstudiedin a group of soldiers,eighteento thirty-nine yea$ old, who wete shown to hav€ coronary disease.3a Fiftysevenpercentof the fatalitieswere associatedwith strenuous activity, and anotler 38 percent with moderate activity. Not evensoldiersspend95 percentof their time hustlingabout. In a similar study, 29 percent of fatal attacks were coincident with strenuousactivity, althoughthe subjeclsspent only 1? percent of their time exerting themselvesto that degree.sThey spent a full halfof their time either inactiveor asleep,yet only about a third of the fatal attacksoccurredthen. And in a third study, 78 percentof fatal attackswere related to activity, while only 22 percentoccurredwith inactivity or sleep.aIn all, a disproportionatenumbero{suddendeathswere associated with st.en-

But it's one thing to die despiresomething,and quite anolher to die becauseot it. lI the wolst thing that could be said aboui exerciseis that it doesn't prevent coronary heart diseaseor death,then thosewho enjoy the sweatand the pain would have no reasonnot to "go for it"-assuming the benefitsof fitness outweigled the risk of injury. But people don't just die in spite of exercise.They die be_ causeof it. And whether death is within seconds,minutes or hoursafter the onsetof the terminal event, that terminal €vent often beginsduring or just aftet exercise. Cardiacdeathsthat occurhours or evendaysafter the onset of symptomsare usuallydue to heart attacks,wnerenean muscle cells are injured and di€ due to inadequare oxygen suppty through blocked coronary artedes. Deaths that occur within secondsor minutes, so-calledinstantaneousor suddendeaths_ are usuallydue ro rhose irregulariliesot hearr rh'1hm called "arrh)1hmias"that are so severethat the heart cannot effec_ tively pump blood around the body. Most people who die of arrhythmias,Iike those who die of heart attacks,have und€r_ lying diseaseof their coronary artedes. Observations tlut incriminate exerciseas a precipitating fac_ tor in cardiaceventsare old and established.Even the weath_ ermanis likely to warn his middle-agedor elderly listenersnot to shovelsnow after a blizzard.But to do a statisticallyproper job of ling€r-pointing, researchershave to figute out the number of such events that would be associatedwith exercise iust bv chance.Chancealone predicts that it you sleep eigtrrhours a day, sit or walk about for another 15 and exert younelf stren_ uouslyfor only about an hour, cardiaceventsshouldoccur in

Other data confirm the same association of sudden death witl phlsical activity. In one communitystudy,suddencardiac death was associatedwith activity in 80 percent of pati€nts, including strenuousactivity in 20 percent.3TIn another, Dr. MeyerFriedman,who helpedformulateandpopulatizethe conc€pt of the Tlpe A personality,reported that more than half of 28 deathsoccurdngwithin secondsof the onsetof any symptoms occurreddudng or immediatelyafter severeor moderate physicalactivity,mostnotablyrunningand jogging.s.Th€ close tempoml relationshipobserved between sevcrc or mooerare physicalactivity and more than one half of the instantaneous coronarydeath cases,"said Dr. Friedman,,,makesus qu€stion whetherit is worth risking an instantaneouscoronarydeath by ihdulging in an activity the possibl€ benefit of which to the humancoronaryvasculaturehas yet to be proved.,'It was also

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OF EXER C ISE

disconcertingthat many of those who died during or imme(ll ately{ollowingexertionhad beenwell accustomedto the specili{ physicalactivity involved. IJ exercisehad no specificcausativeeffect on cardiacevents if chancealone d€terminedthe coronary death rate during cr ercise-there should probably be at most only a few hundrtd suchdeathsper year. When you look at the numben actuallv reported, there is a dramatic causalrelationshipbetweencx erciseand death, a relationshipthat cannotbe dismissed. There are data that giv€ us a truer senseofthe extentof the dsks. A recent study from Rhode Island indicatesthat the an nual coronary death rat€-tlat would include both fatal arrhythmiasand heart attacks-from joggingis about seventimcs the coronarydeath rate during more sedentaryactivities.r'!The prcvalenceof jogging was detcrmined by a telephonesurvcy and the actualincidenc€of death dudng jogging wasestimaled at I per year for every 7,620joggers,or approximatelyI death per 396,000man-hoursofjogging. If you considerthat 30million peoplejog regularlyin the United States,the yearlycostis ovet 3,900lives. Oth€r estimatesand calculationsof the incid€nceofcardiac fatalitiesduring exerciseare evenhigler than thosegivenin the Rhode lsland study of joggers. Studiesof exerciseprograms vary all the way from 1 death for every 7,000 man-hoursof exerciseto 1 death for every 55,000man-hoursof exercise. Therc is no doubt that the older the population, and the mor€ severethe underlyingheart disease,the higher is the likelihood of cardiaccatastrophe. One Canadianstrdy calculatedan incidenc€of I episodeof ventricularfibrillation (a quickly fatal arrhythmia) per 2,500 gymnasium-hours for middle-agedbusin€ssmen.{If a group of men in that age categorywere known to have atherosclerosis or its risk factors, their risk of provoking an episodeof dan-

gerousarrhythmiawhile working out in a gym could be as high as I episodefor every 500 hours of exertion arIn a repo( from Seattle, Washington, 25 exercise-relatedcardiac atrcsts occured among 1,957 men with coronary diseasein a cardiac rehabilitationprogram.l'zSince a total of 374,616hours of supervisedtraining was recorded,the incid€nceof cardiacarrest in tllis groupwasabout l forcvery 80men, and almostI episode for every 15,000man-hoursof ex€rcise.Of great interest, the menwho sufferedcardiacar€st were capableof more physical exercisethan those who did not. When you look at cardiaceventsin general nonfatalheart attacksand arrhythmiasaswell asfatalheart attacksandsudden death-you could justify a claim t}lnt exerciseis a public health hazard.The lnstitute for Aerobics Research,in Dallas. Texas, usedstandardequationsfor calculatingstatisticalprobabilityto estimatethe maximum number of cardiac "events" 10 be expectedin the exercisingpopulation as a whole, basedon the eventsthat had occurredin a sampleof 2,935 adultswho put in a total of 374.798hoursofcxerciseover a 65-monthperiod-41 Dcpendingon the age of thc exercise^, the maximurnrisk estimatesfor men rangedfrom 0.3 to 2.7 cardiacdeathsornonfatal eventsfor every 10,000hours of exercise The risk for women was figured to be nearly double that, or 0.6 to 6 0 eventsfor every 10,000hours of exercise.Basedon their statisticalequa_ tions and their mathematicalcalculations,assumingthat eacb exerciserputs in only about 78 hours oJ exerciseeach year (30 minutesthree times a week), we could expect that between2 and 27 in every thousandmen would suffer somesort ofcardiac ev€ntp€ryear,andso would between5and50 in ev€rythousand women.Even usingthelowestfrgures,if20 millionmen exercise regularly,we could expect40,000of them to bdng upon themselresa heanatlackor uorse;and if l0 millionwomcne\efcis( regularly,50,000of them are also likely to undergoa cardiac

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event. The lowest fiBures,of course, relate to the youngesl exercisers,those least likely to have advancedatherosclerosis. Attempts to pin down the statisticsin exercise-related cardiac deathsand other catdiac eventsseem to indicate that. if anything, available data underestimatethe magnitude of the risk. A number of cardiovascular complications probably go unrecognizedat the time, and thereforeunrepo ed. A person may 6rst experience symptoms as he pours himself a beer after a long workout or strolls home from the gym, and may not relate it to the effort he so recently put forth. A person may not inform othen of feelingsof weaknessor even pain while exercising,so that t}le first they know of his condition is some hours later when, apparcntlysuddenlyand without any link to exertion.he dies. Moreover, bad news is less likely to be publicly reported than good news. In one attempt at a surveyof cardiacevents at community recreation centers, 50 perc€nt of the facilities failed to respond.eAlthough we can't know whether their reports would be lessfavorablethan thosefrom centersthat did respond,t doubt they would be better!

THE DANCERS O F E\ ERCI SE

b1msomesorr ol problem is likely lo confront you ll mal m-rpR"' thopedic.meaabolic.hormonal oI cardiac: it may be or 5eriouq'.* ."uir., t..poru4 or pennanent.Insigni6cant w"'D strenuousexercisei\ really gambling. and you ha\e 1o- _ $e stakescarefully. Do you standlo gajn enoughlo otrs<' r"'r-: hazardslAre the rewardsreatly worlh lhe risks?Mosl tant, is lhere someother way \ane. rensible *k:ii-j,i a crop ol ills? fherr'"' withoulharvesling the lun ot ex€rcise and it is availablelo jusl about every one of us

As for your individual chances of appearing among the sorry statisticsof exercise-relateddeaths,tlat is impossibleto say. Neitherage,nor rcsultsof stresstesting,nor durationof exercise traininghasany reliablepredictivevalue.Manypeople who die tlrough exertionhavedone the sameactivitymanytimesbefore without trouble. Superior athletic performance offers no guarantee againstdying through effort. Perhapsthe gamble is geater if you have heat disease,but therc is an enonnouspool of unrecognizedheart diseasein the population. Exercisedeaths occur, and we cannot identify the individualsat nsk. We can saywith suretythat if you choos€to throw yourself into exercise with the vigor and abandon enthusiasts promote,

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A BetterWoy

This is not an antiexercisebook. It's sjmply the other side of tl|e exercisestory, tbe side few people have heard and some don't want to know- The facts don,t obviare the pleasuresof exercise,but they do say exerciseis dangerouswhen it,s done lor the wrong r€asons.The truth can ptotect you from the claims and aims of othen, and, perhaps, from younelf. you can,t exercisefor your health; you can't run for your life. But vou canexercise for fitnessand torpleasure. andyoucando ir safill. Almost any form of exertion can be kept at a safer level if you don't drive yourself to overdo it. Wiil tf," exception of inlercntly bone-breakingcontact sports such as football and boxing, where inflicting pain and damageon your opponent$ nec€ssaryfor winning, even accidenFriddenactiviti€ssuch as skiing and running can be done with lessrisk of iniury. Take a lessdemandingslope. lor e),ample.or lry cros+couniryskiing insteadof downhill. If you must cover a lot of ground to enjo! youlself,trot, don't lun. Cushionthe impacton yourjointswith

good sneakersand see if you can find a soft running surface suchasa smoothdirt patl iNtead of harshoruneven pavement. There are published precautions for every sport that is beset by muscularand skeletalinjuries; risk call be minimizedif you're willing to €ducateyourself in prudence. Morc worrisome than orthopedic risks are the dangen of cardiac events while performing all kinds of activities. To avoid these, the ultimate dsks, there is only one precaution tllat makes sense:Don't do anythingto the point wherc you feel exhausted, unduly winded or have pain or discomfort in or arcund your It's smartestto plan to limil your exertion from the outset. That meanslong-distancerunning is not in the cardsfor most of us. Joggingmay be all right, but only if you drop to a walk the moment your body tells you to slow down. If basketballis your game, half-court holds most of the excitementand challengeof offenseand defensewithout the exhaustionof running up and down the length oI the full court. Plan a three-setmther than a five-seltennis match; it ought to be suflicientlyexhilarating. And if you're tir€d, sit out the third set. Later, if you want to play again,how about doubles?Planningyour txercise prudently before you start will help you avoid getting into a situationwhere you suspectyou should stop but the pressures of sociability and competition make t}lat s€nsible decision appear gauch€at best, cowardly at worst. There is a subtle but crucial distinction betweenplanning your activity to avoid getting into a prcdicament,and exerting yourself until the onset of symptomsocculs. Waming signals do precedemany disasters,but by the time your breathingis labored,your chesthurts or feels heavyor you'rc lightheaded o{ faint, you may already have gone too far to prev€nt an exercisecatastrophe.Usually tlere is still time to pull back to a saferlevel of eiertionl sometimesthere isn't.

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Er.enhavingreachedthe point aLwhichslmploms are tell, . rr s sl t somelrmes difficultro srop.In lhe hea!ofacririty.wh(n your owo.enthusiasm or othen. eggsyou on. risk ma) seem remote. s JUstroo easj. runningrhe roads of neighbur_ nood or engagingyour friendsin last.paced tolleling;t 'our lhe .l",danser our of your minit and ignorewhar :iil" luu ntghl. under olher circumsrances. feel quire atarmeJabour. Aches.pain\ and heavybreathingare expecledl lhey.reall roo jn the plea\uresand striving ea\yto (lrsmlss of the momenr. Ignoring such symptomsis courting catastrophe. Denial of w^armngsymptoms is a recuringtheme in the studiesandreports ol exercise intudesand deaths.txperiencedathleresand nov_ guilrj ot such imprudenrdeniat.and they are 1*. l,,i: l* equally lrkely ro suffer from ir Then, too, althoughreal trouble is often preceded by warn. ing \ymptomsthat can be recognized. rhar\ nor always'so. In_ lunes.nean a|ackr. evendeathmay occursuddenl)md withoul warning.I neall-out exerciser hasnodelense. Suchcalastrophes are unpr€dictable;prior training and exerciseexperi.nce off", no pmtection To exercisevigorously, to push yourrelf ro greater andgreaterlimirs.because you haveno slmptoms.is ro iubje.r yoursetl10unpredictable and unheralded disasrer. Oy ptanning a more modest level of ex€rcis€you help yourself remain on the side of safetv. some assume that when they ate enrolled in planned, a prescribedor supervisedexercis€program they cun sutetyubrogale the responsibilityfor their own safety. Th€y feel they neednl worry aboul o\erdoingir. sinceLheteret of exerrion hasbeenchosenfor them by others.who musthare a screnrihc ba\js for lhe_choice.O$ers. howeverexpefl rhe) may be, cani reetwn€r rs happeningineideyour body. They can.r Inow ho\r much.how tar and how longyou shouldexelcise on any given dav.

A BETTER WAY

ln anyexerciseactivity,supervisedornot, prescribedorselfchosen,your best guide to the safetyof what you are doing is your own self-awareness. Aiming for a predetermin€dduration of exerciseor a preselectedtarget heart rate is foolish if your body tells you that you're overdoingit. The pleasureof working up a good sweatmay be just as easily gained at a heart rate that is, say, 50 percentof your maximum as it is at 70 percent or someother arbitnrily chosenlevel. And fitnesscan be achieved with less intensity of exertion than the rigid lime-and-effort schedulesoutlined in so many familiar books and articl€son exercise.Prcfessionalathletesneed to adh€reto more rigidly prescribed and severe exercise programs. Their livelihoods depend on it, and they accept the dsks of their occupationsas might a coal miner or an airplanepilot. Recreationalathletes needn't and shouldn't, becausethe gains are illusory and the risks all too real. Sensibleexercisersespousetiis id€a: Listen to your body. This takes a bit of practice;you have to think about how you feel. Your body will speakto you in both generaland specific terms. You know more or less,if you simply think about itand you should think about it whether you have d general fe€lingof well-beingor not. If you feel sick in a generalway, if you have a sensethat you aren't well, you ought at leastnot to exerciseuntil that feeling goesor its causeis determinednot to be related to your physicalhealth Just becauseyou can't pinpoint a sp€cificacheor pain or other symptomdoesn'tmean that everythingis all dght. If you feel you're jusl not right, or are unusuallyfatigued,indulgetlat feelingand stopwhatyou're doing.Generalfeelingsabout youlself are imrlortantand worth listening to- As you exercise, tlink periodically about how you , feel. Appropriate exerciseshouldn't make you feel sick in any Specific symptoms are pedaps harder to interpret because

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with exerciseyou exp€ct to breatheharder, to fe€l your heart pump, to haveyour musclesachesomewhat.The besl guid€line as to \hat is_normal and whal ma' signaldangerjs )our o$n erpe-fience ol how )our body hasusualb respondedto e(enion. || you lhink you-rebrearhing harderthanseemsappropriare .ror,an accu^stomed acrivity. tor e{ample. and especiallyit }ou teetuncomfortable breathing.sLoplhe erercise.painsin areas not directly involved in exercise_an aching left arm in a righthanded tennis player-are also caus€to stop. On the other

teelmitdpainin themusctes )ou.reacrua using

) 111o.tl.r:" ounng,that exercrse,jls probablysateto ignoreir. Cenainll ir yofi chest hurts and you haven,t be€n hit dead center ly a smdshat the ner.you shouldquit on rhe spot. Infacr.anychesr otscomlort-patn.pres\ure.tightnessor an' unusual\ensa_ rron -snoutctbe a signalto stop e\erci{ng. Many committedexercisers rake their pulseas a wa, ol measuing their heart rate at intervalsduring a workout. Ifyou taXe your pulse, it.shouldnl be for the purpose of increasing )our actlvrly,toachieresomearbitrarylraininglevel.but ro Keep trom pushingany\rherenear your age_predrcted maximum. 'oursett Using th€ convenientformula for your preaicted maximumhean rate of 220minusyour age.you can tejt ho\r crose)ou areto thatpointat anylime, As a generdl rule_even rr your healthis excellenl_donie\erciserecreationa y abore about 75 percent of your predicred ma_\imumheart rat;. If you have heart diseaseand you know at about what heart rate you often gel symptoms.you shouldkeep your ac||v|ly ar sucha reverrnatyour hean rate stals well belowit, Ot course,med_ rcarrons maychangethisrelationship of symproms ro heanrare, ano tnjsts a ma er to discuss wrthyour phtsician, Besidesrhe rate ot your heart. checkingyour putse rs userul ro oeted an) trregularities in the hean rhyhm. Somepeople haverrreguiarheartsnormall]. Exercisemay have no eflect or 126

A BETTER WAY

it may even abolishthe irregularity.But somepeople develop irregularitiesonly with exercise,or their basic irregularity at rest increasesas they becomemore active, Thesecan have serious implicationsand are other reasonsto consult your physician. Most exercisersare taught to take their pulseby feeling the largepulsatingartery in the neck, the carotid art€ry. Although the carotid pulseis strong and easyto locate, pressingon that artery can causea suddenreflex slowingof the hea and a fall in blood pressurethat leadsto a blackout. Occasionallyexerciserspressboth sidesof the neck at once in tleir concernto taketh€irpulse.Pressingon both carotidarteriesnot only causes a more severeslowingof the heart, but alsoeffectivelycuts off the blood flow to the brain. It's really better to take your pulse at your wrisl, feeling for the radial artery, and this isn't hard to leam to do, Although listening to youl body puts you in commandof yourself,stoppingwhen somethingalertsyou that all is not well will not endearyou to the exercis€enthusiasts.They will urge you on, tell you that you can do morc and exhort you to r'go for it!" When you persist in slowing down or stopping,you'll earn,not their praisefor your good judgment,but their disdain for your cautiousness, This isn't easy to bear up under, but just remember that exercisers often urgeon othersbecauseofignoranc€.Theydon't know the differencebetweenfitnessand health; you do. They believethe prcmisesof long€vityand better cardiacand mental health; you know better. Spectatorsgratuitouslyurge you on for the vicariousthrill of somebodyelse acbievinga difficult goal. Marathoners,for example,know.the compellingforce of spectatorscheeringand exlorting them. And those to whom 'exerciseis businessencourageyou onward becauseit's money in thei pocket. my should you be their pay check?The sfength

t27

T H E EX E R C IS E MY TH

to resist tie urgings of others and desist ftom exercise should comefrom knowing tiat you're no longer a victim of mytl, an innocenttaken in by your own credulityor by others'claimson you. The pressuresto conform to otganizedexerciseprograms, especially those supported within a corporation, can be un, usuallyintense.A corporationwith a full-time fitnessdirector reportingto the presidentis makinga stat€ment:it is committed to exercise,it expeclsyou to be, too, Wh€n the companyspends money for equipmentand technicalapparatus,when it pays a hefty salaryto a specialistto organize"scientific,,exerciseregimensor contractswith outsidefacilitiesto do the same,your choosingnot to join is saying,in effect, that you know better and that they're wastingtheir money and your time and effort. In a communitywhere most peopleparticipatein an organized exerciseprogram, those who chooseto stand aloof may find themselvesstanding"out" in other areasas well. Yet once you assumecontrol of yourself, know your own body to be the best guide to your own level of activity and no longer allow others to set your pace and goals,you may find t]lat the whole gung-hoatmosphereof organizedexerciseprogramsno longer appealsto you. You may beginto questionthe whole basisof suchprograms.What is there about a particular routineor specialapparatusthat's better than a lessspecial,less rigid form of exercise?Why shouldyou submityourselfto group pressureor to an 'rexpert's"pseudoscientific monitoringof progress loward an arbitrary goal? Their planned and supervised activities aren't any better tlan your own sensible plans fot exercise.And their goalsfor your supposedgood health make far less sensethan your own wish to be more fit, to lose weight or just to enjoy yourself. Th€re arc two ways to combat corpotate or community pressureto participatein structuredexercisewithout losilg esteem

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or appearingnegativeor apafhetic.First, offer your knowledge. Fitnessdoes produce physiologicalchanges,but they are not onesrhal make the heafl heahhier.or lhat improvecoronar) circulation.Fitnessis not relat€dto health at all. Heart attacl$ aren't preventedby exercise;exercisemay provoke heart attacks.And, if pleasureis the goal, there are other activitiesyou Pref€r to grouP exefcis€. Second,select and defend your own form and choice of activity. What is your goal? It may be merely to perform that amount of exercisethat will prevent the small risk entailedin a sedentarylife, or you may wish to retain a level of fitnessyou are now enjoying,or reachfor improvedfitness.You may want only to lose a few pounds.There's notling wrong wit]t any of thesegoals. As for the form of activity, the ideal exerciseshould be a rhythmic and repetitiveactivity. It should usethe large muscle groupsof the body, especiallyof the hip and pelvic areas,in smootl and continuousmotion. It should be simple to do and require no specialtraining or equipment.It ought to be inherently easyto pace, on€ that can be done quickly or slowly, for longeror shorterdistancesand times, and at your own convenience.Ideally you shouldb€ able to do it almostanlnvhere,and aloneor in company.lt shouldbe pleasantand it must be safe. And iI it costsnothing, all the better. Swimmingalmost me€tsthes€crit€ria. The only equipment you need is a bathingsuit and a towel (skinny-dippingreduces even these minimal requirements).The action usesthe large musclesof the shouldergirdle as well as those of the hips and l€gs.The motion is a smooth one, and there is little chanceof injury from awkward moves, sudden stops or twisting turns. There is no poundingor wrenchingpressureon any part of the body. And, althoughyou can sink, you can't fall. But swimmingis a sp€cialskill, and manypeoplearen't good

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enoughat it to get any benefits.It often isn't convenientand it frequentlycostsmoney. Even if there is a pool near home or office,there is a discouraginginconvenienceabout packingup. gefting there, changing,showeringand tlen returning with a wet bathing suit. Swimming must be schedul€dto fit in with otier aspectsof your life, and that isn't alwayseasy. Calisthenicsand aerobic dancing have the advantagethal they can be done at home and at any time convenientto you. Calisthenics,however, usually falls short of having a training effect.There will be somegainsin strengthand limbernessbut the usualsta -and-stopmotion of calisthenics is not continuous enoughto improve aerobic fitness.Aerobic dancingcalls for continuousrbythmic motion, and thereforecanincreasefitness, Both theseforms of exerciseappealto somebecausethere are "ex€rcisealong" programson televisionand tape cassettes that direct the movementsand set the pac€. That's another problem. The speedand vigor urged upon viewersor listeners can subjectthem to much tlle same risks that running would, although they are at least on safer ground in their own home. If you'd lik€ to get the fitnessbenefitsof aerobicdancing,use instructionfor learning the motions, but dance to your own music-slower! Turn off the musicbefore you feel tired; don't wait until some arbitrary length of time haspassed. Bicycling, too, is an excell€ntexerciseand has the added practicalityof getting you somewhere.Many choosero go to work by bicycle. Though bicycling is a continuous,rhythmic motion that usesthe large l€g muscles,it's hard on the knees. By the tim€ manypeopleare in theirforties or fiftiestheirknees aie somewhat arthritic from normal wear ovel the years. The additional stress from bicycling can damage the joint further and can make what might have been occasionaldiscomfort into a real medical problem. Bicycling is probably a bett€r way mainly for youngpeople.

130

A BETTER WAY

The accidentstatisticsfor bikersout on the streetsand roads are also discouragrng.For that reason, some who enjoy th€ motion ofpedaling and whosekneescantake it usea stationary bicyclein the safety, privacy and year-rcundcomfort of their home.Exercisebicyclesoffer you completecontrolof how much to exercise,becauseyou are the one who decideshow long, how fast and how hard to pedal. I suggeststartjng by setting the machineto no pedalingresistanceat all, pedalingslowly at first andincr€asingthe time from perhapsonly a minule to about 15 or 20 minutes.Then the speedcan be incteased,givingyou the satisfactionof watchingmore miles registeredper session. When you're comfo able with 15 minutesor so of fairly rapid pedaling,you cangraduallymake the work harderby increasing the resistance. The ideal exercis€in virtually every respectis walking. Certainly nothing could be more convenient.Walking requiresno specialtraining once you've leamed it as a baby. Any clotles will do- You can do it anywhere,even in the hous€,although the route may get boring and you'll wear a groovein the rug. You can enjoy the companyof others,sinceyou don't require your last breath just to keep going. Walking, lik€ swirnming, usesthe correctlargemusclesfor conditioning;and if you swing your armsfreely and naturally, you get additionalben€fitsthat way. Your pace is obviouslyeasilyvaried, and you can adjust it instantaneously. Th€ trouble with walking is it's so easy.It's so natural that it doesn'tse€mlike exercise.and it's hard thereforeto envision it as beneficial.Well, it does require a bit of specilicdirection to make walking really useful and worthwhil€. Done regularly and at a good pace, conditioningcan be achi€vedso that the body responds to reasonable physical demandswith eas€, withandwithout out excessive heartrate or blood prcssureresponses unusualfatisue.

131

T H E EX ER C IS E MY TH

A BETTER WAY

The amount of walking and the speedyou need depend on . wna1, your goal is, You ma) wish only to eliminate Lhetery sfiall dsk of a truly sedentar)exislence.Sedentary reters to ; lifestyle virtualiy devoid of all but th€ minimal. unsustained physicalactivity neededto walk ftom one room to another in a house or office, or ftom house to car and gatage to office. Ev€n suchprofound inactivity confersbut a small risk for coronary heart disease;physicalinactivity is at the bo(om of the list of secondaryrisk factors. Suchdata as there are senerallv suggestlhat the major risk differenrial tor coronarl Jisease is Detweenvirtualinaqiriry and only mild_ro-moderate acririLy. uotng morethanmild_to_moderate actitily doesn\reducefte isks any further. Although the amountofphysical activity nec_ es\ar)to undoshateverriskis crealedb) inactivhyis pr;abl) small.the actualamounthasn.lbeenmeasuted. As an empiric judgment, I have for a rong tlme r€com_ mendeda daily minimum of one mile of contrnuouswalkins at a paceof threemilesper hour. whichtranslates into a mili in twenty minutes.If peoplecan do that twice a day, I encourage it. But I b€lievethat the once-dailyscheduleis more than suf_ nclentto overcomet]re smallrisk of a sedentaryexistence.you *" t* from the flsk of a sedentar) tife wirhour being P: capable of runninsal all. three-mile-p-er-hour paceis not running, but it,s not saun_ .A tenng either. It doesn'tallow for a lot of window shopping, but nenherdoesit meanyou haveto work up a larherotsweai. ll.s comlonable.indeedofreninvigorating. tor mostpeople.Some, particularlythosep€oplewho have beeninactive for a time due to ertherillnessor personalpreference,find the twenty-minute mile a bit severe.I encouragethem to aim frst for the distance, then the speed.In other words, go for a mile at whatever rate of walking is comfortable;once you achievethe disrance, then pick up the pace.More than a mile distanceand a speedfaster than three miles per hour are unnecessary.

If your goal is to becomefit, how much walking must you do? That dependson what level of fitnessyou want to achi€ve. A twenty-minutemile twice a day can't train you for the superb speedand staminaof an athlete. But if you want to do all the routine activitiesof daily living comfortably, then you don't needmore, You can increaseyour fitnessover a wide rang€by increasingthe distanceand speedyou walk, and by choosinglo include hills and steps.A four-mile-per-hourpace, equival€nt to a mile in fifteen minutes, is quire a brisk walk-faster than that is virtually jogging-and will certainlyenianc€ firness.The point is that by staying within the relatively safe confinesof walking, you can achi€veall the desirablegoalsshort of highlevel atl etic fitness. Remember,you can walk anywhere.The outdoorsis great, but in inclemenl weather you can do it indoors. Some of my patientswalk in the halls and lobbies of apartmentbuildings. ln suburbia,enclosedshoppingmalls are an excellentplacefor winter walking, and indeedfor summerwalking as well, when the outside temperatureand humidity are too high. Becaus€ the pac€ isn't so demanding,and oth€rs can do it comfortably with you, it can be most enjoyable.Companyand conversation are easy,and the sightsand soundsabout you can be savored. And if you really have some place to go, you can ..exercise', youf way to whete you want to be-and no showefor chang€ of clotheswhen you arrive. Walking is the perfect €xercisefor those who have heart dis€ase.Many cardiacpatients,particularlyafter a heart attack, are fiightened of any activity; they limit themselvesunduty, narrow their horizons,sometimesmake drasticchangesin their lives that leave them feeling useless,invalidedand depressed. "Cardiac rehabilitation" programshave becomepopular as a meansof undoing these usually self-imposedrestrictions!but while someindividualsenjoy the camaraderieof groups€ssions, many people donit want to be lumped togetherwith other pa,

132

133

T H E EX ER C IS E MY TH

A BETTER WAY

tientsand may resentregimentation.Ther€ may be no progran) at a convenientdistanceanlrway. Walking will serve the same purpose. It is just about the safest activity you could think of. Anyone who has difficulty duringthe earlystagesofa walkingprogramis probablydestined to havetroubleevenif he or shedoesnothing.Almost all cardiac patientswho are ftightenedof exening themselvescan actuallv do morethantheydo. WhenI stan lhemon a walkingprogram. I set the initial limits so low-perhaps one block at whatever pacethey want-that they are easilyachieved.Just accomDlishing rhis liltle bit of acrivrtyis ofren upliftjng for suchparients I then ask them graduallyto increasethe distanceand then the pace,atwaysmore graduallythan I think they probablycan do. I stressthat there is no rush to achiev€any presetgoals-th€re is lots of time, and the emphasisis on long{€rm achievement. As patientsincreasetheir aclivity without disablingsymptoms the changein them is often rema.kable.Their confidencesoars. theyregaininterestin work andsexualactivity,theythink about traveling-and usuallythey return to all theseactivities. There is no mystery to exercise.you don,t have to be ini_ tiated into membership, to believe in esoteric claims. to Draclice arcanerjtuals. Whateverbene6tsthe human body derivesfrom exertion arc yours whenever you take a good brisk walk o, enJoyyourself-without pushingyourself-at someothet sDort you enjoy. And if you can espousethe saneview of exertionas fully as others espousethe exercisemyth, you'li be doing a world of good for others as well as for yourself. If you can make inrcads on the illusory tlenefits of vigorous exercisewith those who have been seduc€dor coetcedinto wastingtheir money and effort and lavishingtleir hopeson it, you will be helping to check a clangerousand foolish fad. If you can convince a friend that he has no better chance of living to a ripe old ag€ than you by

sprintingpast you each morning, or a spousethat his or her strenuousexerciseregimen is more likely to be a dangerthan a benefitto the heart, you could €ven be savinglives lndeed, the exercise myth may be the first public health menace that can be combatedwithout the expenditureof any money at all. The factsare in; irifotmation is available.The exercisefad is a folly and a danger. It only takes you to spreadthe wod.

134

135

NO TES FO R PAG ES 37- 57

\Tl^,.,-^-

Lt\9[e5 Chrpier 1. Ite Exerctu. M..reghe \. Fin. lares- Tne Conplete Book of Ruhakg. Ne\] I otk; Randon House, 2 Reslal, R. M. Enoneons Excrcising. Ne, yort ?tn6 Maqaziu (j Jan. 1919t:12 17 2n LCleene. D N4x y ot l Rua ag \ c w \ 2 3 . n o c t S e p r . O d . t s r , 0 ) .1 2 t r . , 1. M on6. l. N : Head\ . A. : Rr n e . P A . : R o b e f l '.( C . , p o r k r , t . $ . '| "Coron ry Heart Diseae and PhysicalActivity oI Work.,, t!,.?l 2 ( t 953): 1053- 105?] l] l- ] l2n ChtDter 2. Tbe He.n of the Mftel 1. Shoehan.c. A. "Take lhe Muscles a.d Run, " prrrbian and Spoismdicire a, no. s ( M dl lo8l) . ls . 2 Mol{tovd,J,R'FimessandHealth. Paperpresentedat me.ling ofthe Medical Societyofthe Stateof New York, 1? Sept. 1979. Ch.pa€. i. Wh.i Strcs T6rd Dor,l letl 1. The Connitlee on Exercik, Aneri.ao Hearr Asociation . E ercite Testikp aad T,atune ol Appa4a t H.ahht lndhiluob: A H,dbool, lot phr,;.,.aa. 192. The connirtee on Exe.cic, Anerican Head Association. Ekrcise Tatiag a^d Truinine of lbtliriduals with [email protected] Dise6e or ar Hizh R6k fo, h, Dcr4.pd.nt A Handb@klo. pbsni^. tc,t. 2. rpslein \ L '.t r rr) ol rhe !\ercFe l-CC in lhe Drd8no!\ o( Corondry AneD Dnedc lhe Drrlugue Updcreij. Paperpre'enreddr sympolun. \cw Technique\and Conepts in Cardiotogy.wa\hinglon. D.C., 2 \o\ I Fr oelic he!V , l. . lhom ps on. A . 1 . . t r n g o . V R . . t '. : T r i e b q d \ € , , J . H . I r 0r alr er .M C - v alue o t E x e r c r k r e 'f i n g t o r S c r e e 0 i nAg\ y m p tonatic Men lo. Larent coronary Artery Di*ase. , pfoses i araiirrcular Dbe6.s la (7976\: 265-216 4. Fdis. J. V-; McHenry, P. L.; Jordan,J- W.; Moriis, S. N- .,prevalence a.d Reprodu.ibility oI Exercne-induced Venhiotar Arrh\rhnias Duiop Mdimaf E\erci.e festing ir l\orddl Men. ,4rya.at lou;ml oJ C,tdioi oE 37 \1976), 617 62. 5. SheF, D. S.i Ernst, J. C.: Bri€*, F. R.i Lopez, L. V.i Conde, C. A.i Castellanos, A. ; Myerburg, R. DecreasedFrequency ot Exercise-induced

136

Ventnobr Eclooic Aclivitv in the SecondoITwo ConsecuiveTreadmill Tesls" Cr./lanb, 55 (1977):892-895. 6. Graboys,T. B.; Podrid.P. J.j Lown, B. Tle Reproducibililyof?rolound ST Segnent Depression to Mannd Exerche Treadnil Testi^8. Ame.icon tou.^al ol Catutiotos, 39 (t971): 288. PositiveTesls in Asynp 7, Fr@licher, V. F. ExerciseTestinS-Screening: tonatic Patients.Estimalionof Selerily ot CorcnaryDisease. Paperpre_ in valvular and l$henic Heart sentedat meeting,clinical Perspectives Disease.New York, Nov. 197?. 9. Rchnis. P,i Blackbufr. H. Exe.ciseTests: A Suney of Pr@edures, Safery,and urigarion Experience in Approlinately 170,000'fesrs loumal of ttu Amdican Medi.ol Asociotio^2l1 (1971): 1061 1u66 Conplicalions 10. Sch€rer.D.i Kaltenbsch,M. "FrequencyoILiie-rhrealening Asscialed with stess Tesling." DeuE.he Me.lizi\itche woche^cnnft lu (19?9i:1161 1165. 11. Stnart,R. .,.i Ellestad,M. H. "National SuNey of ExerciseStess Tosting Faciliiies."Ch.rl 77 (1980):94-97. qi 12. Ellestad.M. st ss ?.rr,ra. Philadelphia:F. A. Davis, 1980 Ch.Dcr 4. Th€ Cae Aldmt Lors€rilr |. statiskut Butk n oi thc U4topotiian LiJ?I\rdat? Conpan! Jzn to-' 2. S€gerbe.g,Osborn, Jr. LivinS to Be 1@ New York: charl.s s.nhner\ Sons.1982. 3. Taylor,H. L.; Klepetar.E.: Keys,A. i Parlit. W i Blackbufr, H i Puchncr, T. "Death RatesamongPhysicallyActive a.d SedentaryEdploy.es of the Railroad Induslry. .4neliadn Jout^ol of Publt Heatth 52 (1962): 1@1 t107 l n o d e n e o i C .r o n d J 4 . s h d p r o ,S.,w ci n b l a r r ,L i l - r a n k.( w :sa ce r .R Hetn Dise^e in a PJoul"ron lhured lor Vedrccl( are tHlP) Au.dd, t outtol of Pubtix H.tLh 59. supplenent u, no. 6 (Jn.e 1969): I 101 t\o r kAd n r J"n d C o r o n a r u H e a n 5 P r l l e n b e r se r ,RS.,Jr ;H a l e ,$ .L 51\ 55A Mot$nt\.- \.i Fnsland Juurnol ol U?d(in. 2c2 ttql't 6. ?affenbe.ge.,R. s., Jr.: witg, A. L.; Hyde. R T. 'PbysicrlActivity as an Index of Hearr Attact Risk in Cnllege Alunni. " ,4n..i.an Jouwt of Epitleniolo4t 108 (1918): 161 115. 7. Bassler.T. J. L.lte.. a',cet 2 (1912):711 1r2. 8. Mosis. J. N.; Heady. J. N.; Rame. P. A. PhysiqueoILondonBusben. Lanc.t 2 (1956t: 566-570. 9. Oliver, R. M. 'Physiqueand Serum upids ol Young Lo on Busnen.' Bti^h tounal of Indatial Medicin 24 (r967J: 18t-186 10, Taylor, H. L.: Menoni. A.i Puddu,V.: Monti, M ; Keys. A File Ycan of FolloNup oI Railroad Mea in lt^ly." Cncutotiot 41-12. supplenent I (1910\:l\3-122. U. Keys, A., ed. 'Sunnary: CoronaryHeart Di*ase in SevenCountncs circrlatior 4l-4?, supplemenrI (1970):186 195 12. Menorti, A.i Pnddu. V. Death Rales anong thc Italian Railroad Em

137

I N O TES FOR P A G E S 5 7 - 6 9

NO TES T'O RPAG ES 69- 80

ployees,with SpecialRclerenccto CoronarvHr en" - l. . t r ny al$u, , . - Ln, , o 4npn t a lR ^ ? a r .h , , , i " " l " f r ; ; " '" . , ; . a ' , , I nat m an. r M . : uoer r e. L s . : D r y o o .\ . L , v e t d n d .D . p . : p h i , t i D .I ' . . ' ' Tl, e. I k r Sr dr s or a popd a l r o nC r o u n I n I o . A n e e t e .u n d e rO o . ,

rL Stanier, J. "Recenl Trendsof Major CoronaryRhk FactoBand Corona.y Hcarr Dnease Mortality in the Unired Statasand Olher l.dusldalizel cottrrries_ Prc.e.diags olthe coslnen e on the Dectin. ia Cotono\ earl D ^ n e Vo a a l @ \a r i n n a t H e o n . tu n g . r n d Bto o d tn r ;r r r e , tr 'a r r o n r r I n . l nJr e \u l H ca l h . Be r h r .d a ,M a r vta n d ,2 42 5 Oct 1 9 7 8 . 12. Elrick. H. 'Distance Rumen 6 Modeh of Optinal Hcalth.. phyxicihn 4nd Spotrsne.li.ine9, no, 7 (Jan. 1981):6.t 68. l l M 6 e r . M . - \o n p h "r n d 6 l .g i . I h e rs p y fo r H r ? e n e n \i o d t. tr Fttcd r ve l . Pnaor' CatdnabA\6, no.4 tAorit 1930t: 11 1 4 . I i R n \d . L C .: r ^ l cd v. P.: Vu c"i n B. R . A.: co m "n . p . H e e Fc,n . H K .. N a u g h l o n .l ._ F't( r o t L r n g r .r m Vo Je m r cp h ) .kd t Fr e r cr e o n PldcmcL'poprorcrn\" National Lxe'ose and He,n Dira,e p,oFfl A. chieesoI lhternat Me.licine r12 (\982):22f!-2274 15, Frey_nan, J. F.r McNeil, D. J.i Alaryovic, p.i Mcconathy, W. J. .Effect, nl l2 week..I Lkrcis Tninrn8 on Pja"na Lipid, do Apotil)nprotcrn, in \4iddle ased l/en ucdhhe and s.pace i; spon, a;d i\a,Be ta 4 1 9 8 2 ) :1 0 3 16. t nderee,B. R. i LaFodtaine.T. p.; cotdstein,D. E. .,EfteclsoI Increaws in Triining uprn Blood Lrpidsdnd Ctuco,. Retcredvariabte,. Vpduin. tad S.ientein Sporc oad E,pr.6.14 (1982' t04, 1?. Oel sn, C.j Caeser, q. A. .Time Couse oI Chan8esin Vu._, percent F r a nd .Bl u o dL r p r d \d u d n s c 5 e !e n - q r e k.H ,g r ,- i n r cn "r ly* ,i * no. gan. Vpd\rac and r.,en,c 145p.4, ard Er.;n. t4(ta8t, O. l8 Sce nore r2 19. Allion, T. c.i lammanno, R. M.r Melz, K. F.; Sk.inar, c. S.; Kuller, L. H.i Roberlso., R, J. ,Failure ol Exe.cise10 IncreascHigb Densily Lipoproleinchole{ernl Joutaalot ( r41n. R?hahltunb, t.;o.4 lsepl

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2. Wilhelns.n, L. i Sanne,H ; Elnletdt, D. i cnnby, C. Tibblin,c. i i Wedel. H. ' A Cunr r olt EJ Tr iat ut phv j, d l l r r i n i n g A h e r M J G q r d r b ltn t . r d i n 1 . . . rt?\ekxvc Metl ne 4 tla75) 49r_50a. I R{hnrrer. P A- fhc Ltre! o, L\erci< prc\c prion Jn rhr Recunrn.. t"i,,','"n i Men. Antkui rot,na!.tt aniotlE\ f,l"i,);p,a"t 4 ( allb. V. t lam dt dinm H. : H " M i t d J : I u u n l d , O . I - R e d u c t r o n i,,

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r - ' t he \ alr um l r \ er eher nd Hed r rD r q e d , ep r o . e . r L t r e c . \ o r p r e \ c n h c d d rpewNo r-rrc^e pr.Sirm on Munctrl) rnd Cdrdjotd\.utcr VorbrJitr

Intd'c'$ Amc'^un to"aat^1t !'d,'tuai "w*"t 6. Eckr€in. R. W Effecl of Ererc,seand Corondr ( o*rq (nndfrJl..nor -,.*h,i." Ru"L\;.'l"y;:llr":: a / r or . { at M . A, l. r KG r uk "ti"^ w. r : R e $ n i r / e r . p . A . . C u n t o n g h J mD. A l,liliiij: tll'

c b dle r r l i / d l o n : A n A n g o 8 r d r h t r d n d S c i n r r . CEphk A*(smedr. ( r.u/aro4 o0 (to?o): |l4 Dt t v er df l. M . s . . Hdnunt sC . H . Heptet_Hdrrir J.: $etron.D t .; pra ( M . M illr r . R. . R - F' f ef ls o f E \ e r c n e I | a , n , n B u n L e \ c n r r i . u t _,r rerrormanr perfJ{on In parren..wdh Cnronan A €r "nd MJnrddrat usea<. Amuha4 Jounal oICat.tiotoq\ tTLlv8t).707 qnr ^ " I . Tnnl, l ! H. : Bawot .R D. : o , ( h e M r 7 , M . . . A 1 - t e p r o \ F c L \ e 5r dJ or lne Rc t at r c hhipof Dr f f e r e nHra b i r u a t \o ! d , i o n apt h v ! , d l idnih n tusx md lncrdenceor t{hem,c Heri Dhed.e In \ otunrce;M"te Fc,ieral Anut, ot k" N?\ y!t* 4.ddc4, ot s,En.?. 101 |.o1i\. []etxfe\

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20. Wini;ms, P. T.; Wno,l, P. D.i Haskel. W. L.; Vranuan, K. -lhe rjftcch ofRunning Mileageand Durarionon plasmdLiDoDroteinLevets. lownat ol the Aneti.aa Medxat Axo.i^tion 2 1 (r9'2t: 4614-26js. 2 1 . t f , . . . R . S.: l cc\. A. V _ H i C hd e n i r r L r p o p r o r e i na\ n d th e R r l t o t Arhernrclero\N. \pb E elaadlnur tul rf UpAbineJ6 ( to82, t5,tb tsd8. ,-- Ke\'. A Alpha Lrpotrolern (HDL) (hote{erot ,n rhe Serum dnJ Lhe Risk ol Corcmry Hearr Dncase and Death..,Za,ccr 2 (1980):603_606. -- willians, R. s.; Eden, S.: Ande6en, J. ..Reduced 23. Ep;eph;ine induccd Plalerer Aggregalion Following Cardiac Rehabilitation. i Jo;mal ol catdia. Rehabilration1, no.2 (M^\ 7981):12?-134. 2 a G r e e n .L . H .: Se r .p p r d nF.: . H a n d r d ,R . I p l a te te rAc.i vd r b nD u n n a Erercne-inducedVJn€rdlal l{hena Nca Enslont toumal ol M?dni: 3(2 (1980):19:l 197 Ku6pu.is, A. C.i Luchi, R..l.i Waddetl,C. C.i Miler, R. R. ,.p.oducrion ofcn@bdn8 PlatelctAggregalcsby Eiercne in C.ro.ary patienls.,.Ct cui.rion 6l (l9AO\: 62-65. 25. Sarajas,H S. S. ReactionPatlemsofBtood plateletsin Exercis..,,4d, van 6 ifl (hldiologt 1A (t976)1 176 795. 26. Lether, R. L.; Pickcring, T_ C.: Chien, S.; laragh, J. H. .Efieds ol

139

N O T ES F O R P A GE S 80-95

,

NO TES FO R PAG ES 95- I A7

EreF*ln Pla.mdViscoiry rn_Athtere!and Sedenta4NomatSuble.r. (tuntcot(anlolopr 4 (tg8l\: t72 119 W illiam s R. . S: Logur . E. t - . : L e q s . J . L . : B a r r o n . t . : S l e r d , N $ wdtta.e, A G.i Przo. S. \. -.phy\icdt C-.drrroninB Augnenr" rhe , Fr. DimoNnc.RepoNero veDou\ oc.l6ion h Healrh\ Adutb.1\.\' EnEtahJ rou,nol ol M.dkiac 3O2(lge0):g9'l E l

Chrpter 6. Tbe Mtgh Rutrer L f ollinr . C H. aLv nr h. S. : Car d n e r .M . M . . . p . 'c h o t o 8 h a tF t r n e * a. a phrsical

Funcrion or rums.. A,.h^es4 pb*;t Matit.. ii ibno453(1912\'5O3-5t)R

iiiiti

2. M(MmN D. R -t-a.1qqInndencirS th. p\khologi*t tmpadoi Run. ph.u drs.. (atr,o'niaSchootof prote$iondtpsjchotoeJ. n'ng . Ia79. I Brc { n .R .S .:R d mi R u .D .F .:Tcub.J.M ne ere.Ji pr i oo1r E xei .i ." ,o5rDepresion.-' Prw(ida a,d Spo^npdain.6. no. t2iDe. to?sr.,{ a . An d re s .C . M .: O td n d 8 e\ . B.: prrter..| O. cunni ntham, D. A Kfth n rL z epr.. A.: to n e \.N . t.: B uct. C .. K svanadh. i ,: S hel )harJ, R J .:s u | l o n .l .R ..R e a $ n \fo ,DrotD urtromLre,dr programi i ro,r parFDir. V.driiff aBd l.i.nce in spo,B and E\i;i\p tJ t aptl fronart 5 Mo rg a .w . P : H o ' { m e . D . H .: C trerman.A .: sroter,J -t krase a,

i 7 K u n r J h a l .. 1 .. In Kl i n ,k. l . R r m r n g . th e \e r .H ,Eh . H a r l ,r ',., A o z a " rL Se p t.to To ) :I5 L . 1 8 . S q i k r . K.,'n .h r n td \e r ._ M - BGr o n M d d r ,r n n H d \ t n g H ,Jo r J " rot@ on Medni^e (aorit 1978.t:14 t9. la A M o r r ttsq u i r cl e n ro ' \ a t . p h \\i .i a n a n J sp o t^ l l e , e h on .- G ._ r(De!. he u.dr.rrp 8. no. l2 L98n) 17. 20. Olsen.L The Fdjen \4omdn.n rhe T'dct - /r, /l,,rpf r rAug. tobt/ 24-30. 21. Ashlord, E., in Olsen, E. Seenoie 20, Cbrpr..7. Tle Drgers oa Erercb€ L K o p l a n ,.l P.l * "n ( - d m p b r tl . f F,S,r e .. R K . sh r r te !. R . w : t . | . -'An Fprdem'otogi. StudJ ol lhe B.ne,th drd R,\|\ nt Runnine routnat ot thp Adeti.an VcJtral A\o, iarion r43 ( t9q.,. Jt,R_ r12t 2 . C l m e n r . D ^ 8 .: Td u n r o nJ. . L .: Sm a n .C w .: Vc\r 6 t. l \ L ..A \Jn e J ol (}veru€ RunninsIn lunes.. phrnak oal spotBap,ti.ta. . s rv l98t): 5,17558. ^. "! L B e r s o n .B. L . R o l n r ct.A V. R a m o s C . c.i r h o r n r o n J. .AF Eo r Je dloroStcsrudv ol Squd,htryuti\. Anat,un to aut ot Srot. V?ir\ta? 9 ( 1 9 8 t) l 0 l _ t0 6 4. \lchdfas J A. sporls Vrdi.rne -pal. pre.cnt. and FJtlte. 4acrnaa routMt ol sauta M.dnine 8( 1980):189-194 . C,oprr K. H.. in Lone. C . ed. pltcanok and Rchahititanoh n I!,hph^ n4,fi Ddla. Bdlrrmore wiltiam. & wrt,rn.. 1980. 6 B r o d \ . D .: Ko n e cte .s : D d J.\. $ .. Kr l d .r . S. - A \r u d ) o i c.( ]r trRj u n n r n x I n l u r i c r" R @r i a x ttr .. ;o .5 4 ( l u l t ,9 8 Il 2 2 2 q -. Sheehd, C. A. '.Dosnhitl Demon ph$i.an v^d SpotBacdun? o, n^. I ( J a n .t9 8 l ) :4 3 . 8. Seenote 19, chapter6, 9. Volgan. r,\. P. _NtBrl^e Adoicr'on In R$n.6. phvro,n and \paar netlto^e 1. no.2 (Fcb.]91a) 5t 70. l 0 X e r r . I .Ar h te te \\4 d l to o L o n S r o R e p o n tn i u n e ,...p tJr i .r ,,,n d Jpofrfted'c'rc rU, no. 4 (April t982). 1.27_129. l l . F i r y J a m .q d w h i l e H o u ; S) m p ;,i u m o n p h tn cd tF,r .e \ d n d \D U r l \

*,.,"i; ." " i;1'd:t!:"'{uliI'";t?i?,9:,;?,tr,^1"1,,:.1;x1:

Nomri Adut|s. Ph.D. disa..Inrnute or Ad\aned pslchoro8tcrisrudE. oI AJelphi Univ.sity, 1982. 7. Pi,l{,-F.\ _ Brochemrcal FrcroA Af,fle$ NeurGN.. Beham.,olS.i"a,c 'n 16 (1971):82-91. I Stem. M I: Cleaiy. p^ .Natioml Lxehr* and Hean DFecse prnler. ran€ ffi P$ch@ial Oulmne. Arrhiv^ ot Inknal M.didn. t42 tt ,l

9. Hei@lmann. F. I Bagtey.R. W. ..Responseto physicalActivily prograns and Their Eff€tr on Heallh Beha!io;." public H;obh Repot;85 i97O): 90591r. 10. M@8. V. _Endorphin\a Fremse: A puztingRetrLion htp.. phJnun aa' 1s po, Bac di iae lo, n . 2 ( Feb l o 8 2 r : | l l 1 l _ . 11. S€enore 10. 1 2. Koqer lr / . H W : . Vc Knr Shr A t . - E n d o r p h i n q c n iFl n k e p h d t i n \ . . . A / . van et tn ritettut Mednine,6 (t9E0\. 1_]6 l3 ' A. : Rv e. P R. . . y ox n € . r " E n d o r p h r nai n d M o o dI h o r c e , ] ! . , r 1: r ' . , S:

ifilll'lilfi

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14. Cnier story. "Runsingi .Unity with Narure., MD 23 (April 1979): %

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15. Sheh&. C. A. Do.ot G?otEeShp.ho| \ Matrot Arlvr. lot Runna\. Mounrain Vi€w, Caif.: World hbl,caxons_ 1e7s 16. Doealon,l Run, D@lor. \$_" physi.ian\ Manaeewa, 20 (Sept. 1980) |

140

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taaoAncnfan Mcdrat rlr o!r. ro8nr.2l ^er\

14. Ne|| yotk Titu6, 20 Apnl 1982.Canrirmedin lelepnoneconlenatronwrth author.4 Ocl. 1983. \5. Pans,S. Anericoh M.di@t N?wr (23 Mav 19S0):13. t6. H^ytuad.'r- Aaqican M.di@t News ea May lgso): 13. 17. S€enoie 16, chapt€r6. 1 8 . S u l l i v a n.D . J. SIe s tr a !r u r e ,In R r n n e ^ p a p e rp r e or rhe Anemdr coltege o( SJrgeonc.Chrcagn.O(r. tas,2 . P u b r r cI n te r e { D e p r . o t ftr e p R .b vte n a nH o .p d t, N e r yn ,t. N .y. 2n Shelrer.A L: Ausen.K r. Fr.ici.e-,nduc;d AnoFh\ta\i,. Juutaat Allery and Clinial Immunot s}'66 (1980):106- 1. ^l

141

I NO f ES FO R P A Q E S ] ] O

2t . 22.

118

NO TES FO R PAG ES ] 18 120

Opie, L. H. SuddenDoath and sporr. ra'.d 1 (1975):263-266 4 1 . shepdd,A.J, SuddenDeath: A signincanlHeard of Exercise? an?51 lort&I of spotls Medi.ine I (1974): 101 110. F6sack, K. F.; Hdlwig, R. "cardiac Anest During CardiacRehabihadon: Idendncalion of High tusl{ Patlents. ' Anen oh ,loumal of cordiolog, 49 (1982);915. 43, Gibbons,L. W.; Cooper.K. H.i Meye.. B. M.: Elnon, R, C, Thc Aote Cardia. Risk ol St.enuous Exerci,re. .lountl of the Anencan Medi.al Asaciotio^ 244 \I98o): 1799 1,$1,. 44, Vader, L.; Franklin, B.a Rubeofire,M. "Cardiovasular Conpliqtions of Rerealional Physical Adiany ." Phlsician an l Spotrstuedi.ift 10, tro. 6 (Ju€ 1982):89-96.

2i.

15 . 36.

142

143

nndex Asthma,eiercis-i.dued. 108 14,24,61-63 Athercclerosis, 6 causeof dcathol tunnes, 112, 113 injwy to aneriesand develoPmcot oI. a2,78-79 lipoprcreiN and.2-76

Addiction to exercie, 101-5

Aerobi6 Research. hstitute for. 119 Allergy to ei.rcise, 107 8 Amenon Couese ot CardiologY, 3? Adencan College oI Spons Medi_ Anerican Hedt Asciation. Con_ nitlee on Exercise of tbe, 31, 40 41 An ri.an lownal of Cordiotog.6 Anemia, dnnels GPonsatenia), 108 AngiM p€.toris, 15. 16, 19, 24 Adxieiy,.xe.ciF d therapy for. 8485. 88 90 Atchiv.s ol lakt&l Me.licire, EJ Arh)'thmias, 16, 36-37, 63, 116, 118 Arleri€s. oonary, 14-15 aih.rosleMis of. .Se.Athe.osleollateral bled vesselt,65 67 disa!. rist factos, rcducdon of, 67-81- "Serdto Cotondry heart rp?.tL t!rre's. dise: henostdis and, 76-81 injunes ro. 62, 78-?9 stres t€sts and, 31-32

Bagl.y,Ri.hdd W.,91 Basletbal,123 Ba$ler,Dr. Thona J.,50-51,?6, 111. 115 Bicyclet€stin8.26, 27. .Je.arro Sres tesisand lqang Biaycling.130-31 hemostari.slsEm and, 76 81 runn.rs anemiaGponsanemia), 106 hypert€Niodand corotrdy dise e, 67,6a.69,10-72 strcssteslingand,26,28.30, 32 BostonMaralhon,2, 103 BritishHeonloutMl,s7 5A Brody,Dr. DavidM.,9. 100 CableHealth Network. 5

145

I NDEX

IND E X

Cardiacpade.ts, exerciseand, 11, 41-42, 6i-67 , t79, t33-34 Cardiovascul..di$rde.s, 14-17..t"c ako Alhe.Gclerosis: C.ro.ary heail diseasei rp€.f. srrJe.rr.

Dancin8,aerobi.,130 Dangesof e&rcise,7-121.See dlroInjunesed orherhuards. Dearon,Dr. John,95,103-4 Depressio.,exerci* as lherapyIo., 84,87,89,90 ''DislaneRuners asModetsoI optimalHealth (Ehicksrudy). 71 Double MasterTwo-StepTes1,26

Chapnan, Dr. John M.,57 dd loryevity. 52, 53 risk of @ronary disase ard, 67 68,72-76 Cleoedl,Dr . D- 8. , 98. 9, 100 Colunbia Univesily, 80 Commiitee on Exercise of rhe Ane.icar Hea Asociadon, 31, 40 41 C.op€r, Dr. Kenneth,99 Corondy hearl disea*, 14 17. Se. ako sPecifc subjectt. ascaus ol deathof.unnes and josges, 112, 113. 114. 115 as dangerin exercie, 110-20 death frcn and physical acriviry, 116-20 lonSevity, physical actilily and, 47 60. Seeaba Longevity. dcuPaxons and, 8 9, 48 50, 5260 parrcntsjexeroseand, 11,41-42. 63-61 perlbrmance despite having, 3132, 35. 110- 11 prevenhonof, exercisedd,5-12, 14, 50- 51. 61 63, 111 12 nsk factob, reductionof. 67-81. S." abo Risk facros ot coro, nary disede, rodu.tiotr of, and sl.es testing.25. 30 43 msuspe.ted.42, 110-11,113-15, 124

Injnnes and other hazards,9? avoidane of, 12 29 ignoringoI and addicdonto exer

bl@d dow. ,tce Aneries, @rcnensruation. chatgesin, 105 6 disedes ot. SeeCardiovscular dierdersi coronary hean dis . ei sP.ciltc subkcE. €lectrcardioerans of, 28-30, 3233 fitnessand, 14, 16 23

osleoporosis,105, l(b thernal abnornalities,103, 106-7 vi.al ailnents, 109-10 waming signals,111, 115, 123 27 Intemation.l Congress on Lipoproteinsand Atheroslerqis. ?5 Isonetric hand-griplest, 26

rzr., \A 2,1.n 24,126 thtltttu, 36 37. 12G21 . S.e abo

Eckstein,Dr. Richardw',65-66 El€ctrocddiograms,usein srress t€sting.28 30,32 33 El.ick,Dr. Harcld,71,74 Enotion.l responses to exercise, 82%. Se€alro Psychologicar re sponsesro exercse. Endorphins, exercieed tevelsof, 92-94 Epstein.Dr. Dan.88 89 Equipnentanda@esories. atbletic, 6 7,10 FinnishHearrAsqialio.,

Ht?erfophic c.rdiomyopalhy.I 14t5 H)?othermia, 103, 107

Hand-g.ip 1est. isonetric, 26 Fandler, Dr. Jeflrey B., 113-14 HaN.rd alu6ni. longevitystudyoI, 50. 56 Hawaii, Universily ol, 94 Hoaltb Insurane Plan oI Grealer N e w Yo r t.4 9 .5 4 - 5 5 ,5 6

warningsynproms, deniatot. I I 1, 115 Corporate Challenge Series, 4

Jane Fo^da's rvolkout B@k (Fonda),3

stres tesdng and, 27 43. Seesho Sfess lestsand tesli.g. Heart atlacts, 15-16. 24. S€. drJo Coronafy heart disease. blood cloltidg dnd,76 78 dangerof in exe.cisc.110-20 probability.slathtical,mong er crcisingpopulation.119 20 rehabilitation following, 63-65. 119, 133 34 nsk of, reduclionot. 67-81

58

JoSging andjoggers,1-2, 6, 7, ?4, ?8,86,99, 123.Se?abo Run .ng andrunnes. coronarYhear1diea* ascauseof deathoI jogge6,113 incidence of dead duiingjogging, 118 injuries,101,104.J.e d6o Inju.ies andotherhaards. lournal of theAmencanMeni@lA!

Heinzetnann,Dr. Fred, 91 Heredny,longcvityand, 46, 53 changes

Frieddan,Dr. Meycr,117 F@licher,Dr. Vicior.37 38 Guidelinestor exercise

'.

Kcts, Anal,75 76 Keman.Dr. HowardA.- 105

anodg wonen exer-

tBychological rcsponsesto exercise '

Ht'lerlension,67, 68, 69, 70 72, Src d/'d Blood presure.

trbos. Fred,2, 103 L'EggsMini-Marathon, 2 suing 9cre.al, 12 29

stresstesb as, 44 42

146

t47

T IN D E X

Linits 10exertion(!"r) in stress lesting, 27 28 war.ing signals,111,115, 12327 Lipids,.tbefoslerosis and, 72 76 Lloyd, Dr, GoftreyJ., 102 cholesbrcl levelsa.d, 52, 53 herednyand, 46, 53 linit, biological,44 45 Ma.arhonH)?othesisof, 50-51 occupationsand. 45, 46, 48 50, 52 60 pnjrncal activity and, 44, 47-60 psychos@ial lactob induencing, Ld.gsho.enen, longevitysrudyof, 49-50. 55 56

I NDEX

Myocardialinfarcrion.l5-16

Pithburgh, Univesnyof. Schoolof Popula.ityand exploilalio. of exer

Nation.l Exerciseand Heart Diseae P r o j e d , 6 4 , 7 4 ,q l Nado.al InstitntesofHeahh.35 36 National Spo.tine Goods AssDcia-

4. sup€rvis€d and/ororsanized, 't24-25,\28 29 rapecasseues. 130 lelevisionpro8rans, 130 Psycholoeical.esponses to exetcise. 82-96 annelyand,84 85,84 90 altitudesiowa.d exerlionand. 87 8a deprosionand. 84-8?, 89, 90

Neurotadsnirters,Fychologiel r€sponwslo exerc$eand, 93 96 Ne|9 Engtand tournat of Mednine, 75 Ne*York Maratboo,2, 4, 50 NeN Yo.k Road Run.e6 Club, 4, 50 New lork Runnine Ne||s,4 N e t uY o r k T i n e s , 3 , 7 \ . 5 0 Nicholas,Dr. Janes, 99

endorphinsand. 93 96 maslery, senseof, 91-92 runnelshigh.94-% socialinteradionar.l, 90-91 Publi.ations,popul.., 3, 50 Publi.Healh Repots,91 Pul*, takirs own,126-27

Maralhon .unningand runnes, 2, 50-51, 76, 94, 1n . Se.also Noates, Dr, Timotny D., 1r2. 115 Runningand runnes. Nolewajka,Dr. Andre. 66 @idiac discasesas caus ofdeath, 1L2 103-4, 111.&. ato l.jnardiovascularhealth and, 8,9, 49 'njuries, nes and oiher hazards. and longcviiy,46, .18,50,52-60 Maron, Dr. Bary J.. 114 Oliler, R. M.,53 Ma^hall, D.. Johd L.. 105 Olsen, Eric, 95-96 Marshall,Dr. K. Wayne, 102 3 Masler,D.. Arthur M..9 Opie, Dr. Lionel H., 112, 114, 115 MasterTso-Slep Tesl. 9 10, 25-26, Osborn.Dr. G. R..62 29 30 Osteoporosis among woncn exercisM D. 95 Mental heal$, exercis and, 83 96. Sc?alro Psychological .esponses nedurement ol, D stres lesting, Moldover,Dr. Jonalhan,22 27.2a Morgan,D.. Willian P.,94, 101 Motis, Jereny Noah. 8 9, 48-49, 50, 51-52. 53. 58, 59 Mortaliry rates. .te. Longevily.

Paflenbe.ger,Dr. Ralph S., Jr..49 50, 56 PeachtreeRoad Race,97, 99 Pifis, Dr. Feris N.,89

148

r u n .i n g a n d r u n n e n . l - 2 .6 ,5 0 - 5 1 . 7,1,76. St. ab" Joggingand joggeni Madthon runnins and

oronary heart disease,prevaleac€ anong runne6, 112, 113, 114, 5 injuies and hazards.97-116..t.. also Inju.ies a.d other hazardsi injury, aloiding, 122 23 runrers nigh. 94-96

Saraj6, Dr. H. S- S., 8r] Selection oI exercise activity. 129-35

s.f, 3 Sh e e b a nD. r . Ge o r g e ,2 2 ,9 5 ,1 0 1

Rail.oadworke6, longevitystudies skiinginjuries, 98, 102 of,49, 53-54,56 57 RisLfactoGof @rcnarydisease..e- smoking. cigarerte,and .isk of 610dDction of,61-81 nary disease.67-68, 69,76, choleste.ol,67-68. 72-76 78 ollate.almrona.ycndlalio., 65he$ostasis and.?6-81 hypenensior, 67.68,4)9,?0-?2 lipoproreins,72 76 pnnary faclo$. 67 76 p.idarypreventon,61 63 se@ndarytaclors, 67 seoddarypreventio.,62-65 snoting,ciSarerte. 67 68,69,76,

St.nler, Dr. Jereniah, 69 Stewa.d,Derek G.. 115 Stres, norraliry and. 46 Stressteslsand testing,9-11, 24-43 birycle, stationdy exercise, 26, 27 blood pressureand, 26, 28, 30, 32

1a '

lertiaryp.evention, 63,65 Roberls,Dr. william c., 112 Rowndan,Dr. RayH.,68

119

eledrocardiograns,u* oI, 28-30, 32 33 end poinis ol, 27 28 eovironmental tactos affecrinS re

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