The Journal of the American Medical Association of has made itself popular (or not) by releasing the results of a study on how much exercise older women need to take to ward off weight gain noting that in 2008 the US  federal guidelines were “at least 150 minutes per week  of moderate-intensity activity”.   The study looked at women who were on average over 54 at the start of the 13 year study.

They found that exercising an hour a day helped women who were already a healthy weight range (BMI 25 or less) to maintain their weight. Others needed to combine calorie restriction with exercise to lose weight.  

 WebMD has a good interpretation of the study findings:

Exercise and Weight Control: Study Details

Lee and her colleagues followed more than 34,000 women who had participated in the Women’s Health Study. The women’s average age at the study start in 1992 was 54.

Women self-reported physical activity and weight at the study start and at years, 3, 6, 8, 10, 12, and 13.

All women ate a normal diet, and there weren’t instructions to reduce calories.

The researchers classified the women into three activity groups, depending on the level of activity:

• One group was active less than about 150 minutes a week — the amount of moderate intensity activity recommended for health benefits (but not necessarily weight control), according to 2008 federal guidelines.
• A second group was active more than 150 minutes a week but less than 420.
• The most active group got in 420 or more minutes a week of moderate activity, or about an hour a day.

The researchers looked at physical activity and weight gain over intervals averaging three years.

Exercise and Weight Control: Study Results

Overall, Lee says, all three groups gained weight over time — an average of 5.7 pounds.

But the more active the women, the less they gained. ”Compared to women in the most active group, women in the two lesser active groups gained more weight,” Lee tells WebMD. ”Compared to the most active women, the two less active groups were more likely to gain 5 pounds over the three-year period. The second most active group was 7% more likely to gain the 5 pounds, and the least active group 11% more likely.”

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.”

So what does this mean for you?  If you have a BMI of 25 or less, you can get away with one hour exercise a day with no cut in calories. If you cannot do one hour’s exercise a day then along with the over-weight you will need to cut calories as well as exercise to decrease then maintain your weight.  How much of each can be worked out by looking at your BMR.

This entry was posted on Wednesday, March 31st, 2010 at 1:38 pm and is filed under Health & Fitness, News. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.