because aging isn't enough fun already
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.
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.