In fact, this evidence suggests that exercising regularly during middle age and beyond is an enormously effective way to promote just the sort of old age boomers dream about: independent, robust and free of chronic disease or disability. "If you had to pick one thing, one single thing that came closest to the fountain of youth," says James Fries, M.D., a pioneer researcher on healthy aging at Stanford University, "then it would have to be exercise."
Exercise maintains healthy blood vessels for good circulation in the body and brain. It also helps people manage their weight and cope with stress. And exercise stems age-related losses in bone density and muscle mass while it keeps the heart and lungs strong.
The bottom line, reflected in dozens of studies, is that people who exercise, on average, live longer than those who don't, with a reduced chance of heart disease, high blood pressure, stroke, type 2 diabetes, colon and breast cancers, depression, falls and even mental decline.
"Exercise seems to be one of the key factors that distinguish people who have a healthy old age from those who don't," says Suzanne Leveille, a professor of nursing at the University of Massachusetts Boston who is conducting research on disability in older people. "Being sedentary is a known risk factor for just about every poor health outcome, from being hospitalized to ending up in a nursing home, and even to mortality."
In terms of longevity, regular exercise seems to have an impact that few other health measures can match.
Compared with sedentary men and women, people who did an hour and a half of moderate-to-vigorous physical activity weekly — less than 15 minutes a day — were 20 percent less likely to die during a follow-up period of more than a decade, according to a 2008 report by a federal guidelines committee. And when these exercisers spent more time moving — an hour a day — they cut their risk of dying by a whopping 40 percent.
Moreover, a 21-year study by Fries and colleagues at Stanford, published in 2008, followed middle-age members of a runners club and compared them with men and women who didn't exercise. As they aged, the runners stayed spry — continuing to perform everyday activities — for 16 years longer than the other group.
Studies also strongly suggest regular exercise helps keep us sharp. A federal report concluded that while being physically active in midlife and beyond may not prevent dementia, it seems to delay its symptoms. Research has shown, too, that regular walking helps delay or even prevent the brain shrinkage that heralds the onset of dementia.
So are the new seniors, with their treadmills and weight machines, set to defy old age? Boomers, especially those who are educated and well-off, do engage in more leisure time workouts than their parents did; they also eat more fruits and vegetables, smoke considerably less, and have access to better medications to control high blood pressure and cholesterol, says Ali Mokdad, a professor of global health at the University of Washington. But Americans born into post-World War II prosperity also are the first generation to face social changes, global in scope, that promote a sedentary lifestyle and calorie-rich diet. "We work longer hours," says Mokdad. "We commute longer. We sit down to the TV and computer more than our parents did." And "we're paying for it by having higher rates of obesity."
Indeed, some experts predict obesity will be the boomers' Achilles' heel, negating their other health advantages as they age. Still, boomers can start now to eliminate many health risks by — you guessed it — exercising. "Right now, we are lousy at getting people to lose weight," Fries says. "But we can get people to start exercising and keep it up. It's a much more effective way to pursue the health policy."
Katharine Greider lives in New York and writes about health and medicine.
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