CHICAGO – Rev up the treadmill: Sobering new research spells out just how much exercise women need to keep the weight 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 middle-aged women followed for about 13 years. Most were not on calorie-cutting diets. The women gained an average of almost 6 pounds during the study.
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.
The study appears in today’s Journal of the American Medical Association. Only women were studied, so the researchers from Harvard’s Brigham and Women’s Hospital said it’s uncertain whether the results would apply to men.
The research “reinforces in a nice, clear way the idea of how difficult it is to maintain a healthy weight in our society,” said Foreyt, of the Baylor College of Medicine in Texas.
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.
The study underscores some inevitabilities about aging. Men and women often put on weight, partly because their metabolism slows down. But that probably has less to do with it than people’s natural tendency to become more sedentary, without changing their eating habits, Lee said.
Hormonal changes in menopause also can make women prone to weight gain, especially around the belly.
Women who don’t want to take on so much physical activity will need to cut back on calories to prevent more pounds.