Differing exercise requirements for aging women

A recent study (appropriated from here) underlines something we've discovered to be true over the last few years: that women's exercise requirements actually increase with age. Or their dietary intake needs to decrease. Or a combination of the two.

In our experience, exercise and a popular diet (South Beach) were not enough to bring my 50-year-old-plus wife's weight down. She followed that diet pretty scrupulously and we were fairly active--much more so in the summer than in winter, since this dates to before we started strength training and riding stationary bikes over the winter. But we still did quite a bit of walking during the colder months. After an initial weight loss of a few pounds on that diet and intermittent exercise regime, her weight would start to go back up. It was obvious something wasn't working.

What finally brought the weight down and kept it there (she was up to about 170 and is at 125 now--and no, I don't want her to lose any more) was cutting the South Beach diet portions down and increasing exercise. She replaced one of the daily meals in the South Beach plan with one of their recommended snacks, to be specific. And we began our current, year-round exercise regime.

So she eats two South Beach meals per day and the third meal is replaced by a South Beach recommended snack (e.g., apple with peanut butter or small shrimp cocktail), and in addition she has the other two snacks the diet advises (one between breakfast and lunch and one between lunch and dinner). That eating plan in combination with our new exercise regime, has allowed her to lose about 45 pounds and keep it off (fingers crossed!). She's been at the target weight for close to 6 months now, incidentally. I'm very happy with that and so is she.

In any case, the study I mentioned seems to offer an explanation for why it was so difficult for her to steadily lose, then keep off, the weight. The article follows.

Women Need 60 Minutes Daily Exercise To Prevent Weight Gain -Study
By Jennifer Corbett Dooren
Dow Jones Newswires

WASHINGTON -(Dow Jones)- A new study shows women need 60 minutes of moderate daily exercise to prevent weight gain as they age if they consume a normal diet.

The findings suggest women need more exercise than the current guidelines of 150 minutes a week, or 30 minutes five days a week, of moderate-to-intense activity. The study is being published in the March 24/31 edition of the Journal of the American Medical Association.

"I don't want people to throw up their hands and say I can't do it," said I. Min Lee, the study's lead researcher and a doctor and associate professor at Harvard Medical School and Brigham and Women's Hospital in Boston.

She says women who consume a normal diet and are already at a normal weight can beat middle-age weight gain by working out intensely for 30 minutes a day by running, cycling, swimming laps or working out at a gym.

"If you are willing to sweat it out you can do less," Lee said. Weight-gain can also be prevented with 60 minutes of moderate activity like walking, a leisurely bike ride or playing catch, for example.

Federal exercise guidelines of 150 minutes a week of moderate-to-intense activity are designed to prevent disease and obtain other health benefits. However, a 2002 report by the Institute of Medicine suggested 60 minutes a day, or 420 minutes a week is needed to prevent weight gain.

Lee explained that the basis of IOM's findings have been questioned so she and other researchers decided to look at the issue again with a group of women participating in the federal Women's Health Study. She also said the goal of the study was to look at women who weren't dieting and were consuming a normal diet to see what impact physical activity has on weight.

The study looked at 34,079 healthy U.S. women who consumed a usual diet from 1992-2007. The women in the study were all age 45 and older at the start. The average age of women in the study was 54.

The women were given a questionnaire about the amount of exercise or activity they engaged in per week at the study start and then at three-year intervals. Women's exercise activity was tracked for an average of 13 years while weight changes were tracked over a three-year period.

Overall women gained an average of 5.7 pounds in the study. However, women who were normal weight, or those with body-mass index of less than 25, maintained their weight if they exercised for 60 minutes a day. Women who exercised less generally gained weight.

Lee said that for overweight or obese women that 60 minutes a day of exercise wasn't enough to maintain weight, suggesting calories also need to be cut.

"These data suggest that the 2008 federal recommendation for 150 minutes per week, while clearly sufficient to lower the risks of chronic diseases, is insufficient for weight gain prevention absent caloric restriction," the study author's wrote.

As I've written earlier, at certain times of the year (mostly in winter) we might exercise as little as 140 minutes a week--a bit less than what the current guidelines suggest for women. When the weather allows cycling outdoors, however, we exercise far more than that. Heck, any typical Saturday or Sunday when the weather is nice sees us doing a minimum of 150 minutes on the bike at one time, and we might even do twice that or more.