Researchers: Older women need 1-hour workouts daily to fend off flab

CHICAGO -- Rev up the treadmill: New research spells out just how much exercise women need to keep the flab off as they age -- and it's a lot.

At least an hour of moderate activity a day is needed for older women at a healthy weight who aren't dieting. For those who are already overweight -- and that's most American women -- even more exercise is called for to avoid gaining weight without eating less, the study results suggest.

"We all have to work at it. If it were easy to be skinny, we would all be skinny," said John Foreyt, a behavioral medicine expert who reviewed the study but wasn't involved in the research.

Brisk walking, leisurely bicycling and golfing are all examples of moderate exercise. But don't throw in the towel if you can't do those things for at least an hour a day. Even a little exercise is good for your health even if it won't make you thin, the researchers said.

Their findings are based on 34,079 non-dieting middle-aged women followed for about 13 years. The women gained an average of almost 6 pounds during the study.

In this March 22, 2010 photo, Janet Katzin, 61, of Jericho, N.Y., exercises on an elliptical machine at X-Sport gym at the Roosevelt Field Mall in Garden City, N.Y. (AP Photo/Kathy Kmonicek)

Those who started out at a healthy weight, with a body mass index less than 25, and who gained little or no weight during the study consistently got the equivalent of about an hour of moderate activity daily. Few women -- only 13 percent -- were in this category.

Few already overweight women got that amount of exercise, and the results suggest it wasn't enough to stop them from gaining weight.

But Jackson physical therapist Justin Franke, with Select Physical Therapy, said the recommendation should extend across the board.

"Everyone of every age needs at least 60 minutes of moderate activity every day regardless of age or gender" and either more intensity during that hour or more minutes to the workout if you're trying to lose weight, he said in an e-mail interview.

The results echo what gymfuls of middle-aged American women see every time they step off the treadmill and onto the scale.

"One reason women have to exercise more as we get older to maintain our body weight is because we lose muscle mass which decreases our metabolism," said Fitness Plus operations manager Sandy Duncan in an e-mail interview. She said adding strength training to a workout will help slow or reverse this.

"Of special interest to older adults is evidence that muscle-strengthening exercises can reduce the risk of falling and fracturing bones and can improve the ability to live independently," she said.

Janet Katzin, 61, a "slightly overweight" marketing director from Long Island, N.Y., who exercises for an hour twice a week, said she was thin as a younger adult, but the pounds started creeping up after she had her two children in the 1980s, despite exercising and watching what she eats. "It's just extremely frustrating and discouraging."

The study appeared in a recent Journal of the American Medical Association. Only women were studied, so the researchers from Harvard's Brigham and Women Hospital said it's uncertain whether the results would apply to men.

The results bolster a 2002 Institute of Medicine report that emphasized the importance of balancing diet and exercise and recommended at least 60 minutes daily of moderate activity for adults and children. But the study also indicates that the 2008 U.S. guidelines urging about a half-hour of exercise five days a week won't stop weight gain while getting older without cutting calories, said Dr. I-Min Lee, the study's lead author.

Hormonal changes in menopause also can make women prone to weight gain, especially around the belly.

Still, Lee emphasized that the benefits of exercise extend beyond what you see in the mirror, helping keep the heart healthy and protecting against chronic disease even if you don't get enough activity to lose weight.

But, Franke said, losing weight should be a goal for those carrying extra pounds. "If you are just slightly overweight remember that for every pound of fat there is one more mile of blood vessels that means extra strain on your cardiovascular system," he said. "There is also one extra pound of weight on joints that are only made to hold a certain amount of weight and it doesn't take long for the pounds to add up."

Katzin, a size 14, said she does an hour workout twice a week with weights, an elliptical machine and bike. "I know I should go more, but that's all I can swing," she said. Katzin was not involved in the study.

The researchers analyzed data on women who took part in a long-running federal study. Participants were 54 on average at the start and periodically reported how much they exercised and weighed. They also reported eating habits at the start, but not throughout, a limitation the authors acknowledged. Lee said the women's eating habits were thought to be typical of American women who aren't dieting.

People often don't realize how quickly a bag of chips, an extra piece of cheese, a few glasses of wine or a candy bar add up.

"You can eat a candy bar in two minutes. Most are at least 200 calories," and to burn that off requires walking for about an hour, Lee said. Knowing that equation can help people make wise decisions about activity and food choices, she said.

Features editor Chris Harris contributed to this report.