Fit Beats Fat for a Longer Life

Obesity Has Lesser Influence on Death Rates in Older People, Study shows

Reviewed by Louise Chang, MD on December 04, 2007

Dec. 4, 2007 -- Staying fit is more important than losing fat for older adults, new research suggests.

Fitness was found to be a strong predictor of longevity in the study, which involved adults ages 60 and older, while obesity had little influence on death risk.

Study participants who were more fit, as measured by treadmill exercise testing, had a lower risk of death than those who were unfit, even when they were overweight or obese.

A low level of fitness was associated with a higher risk of death from all causes.

The study is appears in the Dec. 5 issue of The Journal of the American Medical Association.

University of South Carolina diet and exercise researcher Steven N. Blair, PED, says it is increasingly clear that carrying excess weight is less dangerous for older people than for people who are young or middle aged.

While he acknowledges that the idea has its detractors, Blair points out that other studies have also shown this to be the case.

"I don't want to sound like an apologist for obesity," he tells WebMD. "But in older people it is not as important a determinant of mortality as it is in younger people."

Age, Obesity, and Fitness

The newly reported study included 2,603 people in their 60s and older followed for an average of 12 years.

All the participants received detailed health examinations upon study entry, as well as the exercise fitness test and measurements of their body mass index (BMI), waist size, and body fat.

The 20% of participants who performed worst on the treadmill test were considered least fit. Men fell into this category if they could remain on the treadmill for no longer than 7.8 minutes. For women the cutoff was 5.5 minutes.

Age, low fitness level, and having multiple risk factors for heart and vascular disease at study entry were all found to be independently associated with death risk among study participants.

Better fitness was associated with less likelihood of diabetes, high cholesterol, and high blood pressure. Death rates for those with the highest fitness levels were less than half that of those who were physically unfit.

But being overweight and even obese was not an independent predictor of death risk.

Among people who were fit, survival rates were similar for normal weight, overweight, and obese people.

Blair points out that 46% of the people in the study with a BMI of 35 and over (considered extremely obese, by most estimates) did not fall into the lowest or even second lowest fitness categories.

Exercise Linked to Longer Survival

The study is not the first to find fitness among the elderly to be one of the best predictors of survival.

In research reported in 2006, Anne B. Newman, MD, MPH, and colleagues from the University of Pittsburgh found an inability to walk 400 meters, or about a quarter of a mile, to be associated with an increased risk of death in people between the ages of 70 and 79.

Newman tells WebMD that while fitness appears to be a more important predictor of survival in older people than weight, many unanswered questions remain, such as why obesity appears less dangerous in this age group than in younger people.

"It may be that that the diseases associated with obesity, such as diabetes, arthritis, and heart disease, are already evident by late middle age," she says.

Because it was also not clear how long the obese people in the study had been overweight, she adds that their improved survival may not reflect the dangers of a lifetime of obesity.

"People definitely don't need an excuse to gain weight," she tells WebMD. "But we have found that heavier older people do not appear to be as sick."

Blair says public health messages aimed at keeping older people healthy should focus more on physical activity and less on weight loss.

Walking or engaging in similar exercise 30 minutes a day, five days a week is enough for older people to achieve moderate physical fitness, he says.

"The message these days is that obesity is the worst public health crisis we've ever faced," he says. "If physical activity gets mentioned, it is usually thrown in as an afterthought. But our research over the last dozen years, including this study, shows that physical activity and fitness play a big role in health."

Show Sources

SOURCES: Sui, X., The Journal of the American Medical Association, Dec. 5, 2007; vol 298: pp 2507-2516. Steven N. Blair, PED, departments of exercise science and biostatistics, University of South Carolina, Columbia. Anne B. Newman, MD, MPH, professor of epidemiology and gerontology, University of Pittsburgh School of Medicine. Newman, A., The Journal of the American Medical Association, May 3, 2006; vol 295: pp 2018-2026.

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