Work Out Now, Weigh Less in Middle Age

Everybody knows the importance of exercise in keeping weight down. What's more surprising is that physical activity in the present may prevent weight gain many years into the future, according to a study out today in the Journal of the American Medical Association. Researchers who followed 3,554 people over two decades found that men who stayed highly active gained six pounds less on average after 20 years than their low-activity counterparts did. For women, the difference was a whopping 13 pounds. Waistlines were trimmer for both sexes in the high-activity groups as well. Those studied began as 18- to 30-year-olds. Their 38- to 50-year-old selves showed that consistent commitment to physical activity may mean fewer pounds tacked on during the years notoriously threatened by jiggly bellies.

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Highly active, moreover, doesn't necessarily mean marathoning or pumping iron for an hour. While the study used a complex formula that assigned scores according to how long, how often, and how intense the participants' activities were, highly active was equivalent to spending roughly 2½ hours a week getting your heart pumping, like in a sport, brisk walking, or even gardening, says Arlene Hankinson, lead author of the study and an instructor in the department of preventative medicine atNorthwestern University Feinberg School of Medicine in Chicago.

Yet only about 12 percent of the men and women studied fell into this elite group. The reason, says Hankinson, is consistency. "It's not that it's hard to achieve high levels of activity," she says. "It's that it's difficult to maintain them over time." You can't have an on-again, off-again relationship with exercise. You have to commit.

That's unlikely to happen unless you enjoy yourself. "Pick activities that provide continual motivation for you," says Hankinson, whether it's step aerobics, karate, dance, or racewalking through the park. Just make sure it gets your heart rate up. (Get your target heart rate from this table  from the American Heart Association.) "Whatever activity you do, the whole point is that you're doing something that you are going to maintain over a lifetime," says Hankinson. "I don't want to ever give the impression that it's only certain types, because that just limits how people incorporate activity in their daily lives."

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Your busy life may compel an unconventional regimen, and that's fine, says Jeanne Doperak, a sports-medicine physician at theUniversity of Pittsburgh Medical Center. "It may mean turning some music on with the kids and dancing around the living room for a half hour," says Doperak. "It may mean going to the zoo for the day and walking a little faster between each exhibit. It may mean going with your daughter to her roller skating party on Friday night and you renting skates and skating with her." You might also look at the world around you as your gym. Take the stairs. Put down the phone and zip over to your colleague's office instead. Park farther away. Get off the bus or train a stop early. "There's a Starbucks on every block, it seems," says Hankinson. "So if you're breaking for coffee, choosing to go the extra block or two to the store further away" is another trick.

Given the time of year, a New Year's resolution can't hurt. But don't make it unattainably lofty. Good goals challenge you but aren't so difficult that you give up in a few weeks. Think long term. If running 50 minutes one day means you'll be spent the rest of the week, go easy on yourself—it'd be much better to take a 30-minute daily run if it means you'll keep it up for many years, says Hankinson.

Although the study participants who were highly active were as young as 18, it's not too late to get moving if you're far from teenage years. "Hope is not lost," says Hankinson. "Incorporating activity into your daily life—it's never too late to make that decision." It's crucial, in fact, at any age to help avoid obesity, diabetes, and heart problems  that only get more dangerous as you grow older. Prescribe yourself some physical activity. "Exercise is medicine," says Doperak. "Truly, the best thing we can probably do for ourselves is get up and get moving."