2010-03-24 09:37:17
By LINDSEY TANNER, AP Medical Writer Lindsey Tanner, Ap Medical Writer Tue
Mar 23, 5:35 pm ET
CHICAGO Rev up the treadmill: Sobering 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 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 results echo what gymfuls of middle-aged American women see every time they
step off the treadmill and onto the scale.
"Talk to any group of women and they all say the same thing," said Janet
Katzin, 61, a "slightly overweight" marketing director from Long Island who
exercises for an hour twice a week.
Thin as a younger adult, Katzin said 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 appears in Wednesday's 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 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. But Lee said they should do so in ways they
can live with permanently, not with drastic diets that are doomed to fail.
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.
Katzin, a size 14, said she does an hour workout twice a week including
weights, an elliptical machine and bike. "I know I should go more, but that's
all I can swing," she said.
She also has switched to diet soda and eating fewer treats, but that hasn't
curbed her weight. 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.
Dr. Howard Eisenson, who heads Duke University's diet and fitness center, said
it's likely some women underestimated what they ate and overestimated how much
they exercised, which could have skewed the results.
Still, Eisenson said he doesn't encourage anybody to try to lose weight by
exercise alone. To combat age-related weight gain, "you're fighting in many
cases a losing battle" if you don't also cut calories, he said.
That doesn't mean you have to starve yourself, but it does mean watching what
you eat and avoiding frequent indulgences. 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.