Exercise 1 Hour a Day to Avoid Weight Gain
Women Who Maintain a Healthy Weight Get 60 Minutes a Day of Moderate Activity, Study Finds
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Exercise and Weight Control: Study Results continued...
The two lesser active groups were about equal, however, in the amount of
weight gained, she says.
Initially, Lee says, the relationship between physical activity and weight
control looked like it applied to everyone. But it did not.
Lee and her team also looked at a subgroup of women -- those who started out
at a healthy weight -- that is, with a body mass index or BMI of less than 25
-- and maintained a healthy weight throughout -- that is, gained less than 5
pounds at the three-year interval. Thirteen percent of the women, or 4,540, had
a BMI lower than 25 at the study start and maintained a healthy weight
throughout. ''We found the relationship between physical activity and less
weight gain held only for the women with a BMI of less than 25."
For those whose BMI was 25 or more, ''there was no relationship between
physical activity and weight gain, but perhaps because they just weren't very
active," Lee says. For these women who are already overweight, she says, it
seems exercise must be combined with calorie reduction to control weight.
The women who started at a healthy weight and kept their weight healthy
consistently got in an hour of moderate intensity physical activity daily,
Lee's team found.
Lee isn't sure whether the findings apply to men as they age. "U.S. men [as
a whole] are more physically active than women," she says, and less likely to
be obese. Lee has served as a consultant for Virgin HealthMiles, a worksite
activity program, and is on its scientific advisory board. The study was funded
by the National Institutes of Health.
Exercise and Weight Control: Hard Work
The study results are no surprise to Suzanne Phelan, PhD, assistant
professor of kinesiology at California Polytechnic State University in San Luis
Obispo and adjunct assistant professor of research at Brown Medical School in
Providence, R.I., who has researched the topic.
"To keep a normal body weight is hard work," she says. As you age, she says,
"you have to exercise a lot whether you are normal weight or maintaining a