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Fitness predicts longevity better than fat: study

Dec. 5, 2007
Courtesy JAMA
and World Science staff

Old­er peo­ple with bet­ter cardio-respiratory fit­ness ap­pear to live long­er than un­fit ones—in­de­pen­dent­ly of their lev­els of body fat, ac­cord­ing to a new study that rec­om­mends a daily brisk walk for fit­ness.

Pre­vi­ous research found that obes­ity and in­ac­ti­vity each can pro­duce a high­er risk of death in mid­dle age. Wheth­er this is al­so true for old­er peo­ple has been un­cer­tain, said the auth­ors of the new stu­dy, pub­lished in the Dec. 5 is­sue of the Jour­nal of the Amer­i­can Med­i­cal As­socia­t­ion.

Xue­mei Sui of the Un­ivers­ity of South Car­o­li­na, Co­lum­bia, and col­leagues stud­ied a sam­ple of 2,603 wom­en and men aged 60 or old­er. They found that those who died were old­er, had low­er fit­ness lev­els, and had more car­di­o­vas­cu­lar risk fac­tors than sur­vivors. 

Fit sub­jects had low­er death rates than un­fit ones with­in al­most eve­ry lev­el of adi­pos­ity, or body fat, the re­search­ers found. In most in­stances, they re­ported, death rates for those with high­er fit­ness were less than half the rates for those who were un­fit.

The fat but fit “had a low­er risk of all-cause mor­tal­ity than did un­fit, normal-weight, or lean in­di­vid­u­als,” the team wrote. Past find­ings of links be­tween high fat and mor­tal­ity are probably ex­plained by the fact that lean­er in­di­vid­u­als tend to be fit­ter, though this is­n’t al­ways true, the au­thors wrote. 

A daily brisk walk of 30 min­utes or more “will keep most in­di­vid­u­als out of the low-fit­ness cat­e­go­ry,” and probably en­hance chances of a long life, they wrote.

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Older people with better cardio-respiratory fitness appear to live longer than unfit adults—independently of their levels of body fat, according to a new study that recommends a daily brisk walk for fitness. Previous studies found that obesity and inactivity each can produce a higher risk of death in middle age. Whether this is also true for older people has been uncertain, according to the new study, published in the Dec. 5 issue of the Journal of the American Medical Association. Xuemei Sui of the University of South Carolina, Columbia, and colleagues studied a sample of 2,603 women and men aged 60 or older. They found that those who died were older, had lower fitness levels, and had more cardiovascular risk factors than survivors. Fit subjects had lower death rates than unfit ones within almost every level of adiposity, or body fat, the researchers found. In most instances, they reported, death rates for those with higher fitness were less than half the rates for those who were unfit. Fat but fit individuals “had a lower risk of all-cause mortality than did unfit, normal-weight, or lean individuals,” the team wrote. Past findings of links between high fat with mortality are probably explained by the fact that leaner individuals tend to be fitter, though this isn’t always true, the authors write. A daily brisk walk of 30 minutes or more “will keep most individuals out of the low-fitness category,” and probably enhance chances of a long life, they wrote.