Publications
Partners
People who keep up an active lifestyle into middle-age gain fewer pounds and inches over time and the benefit may be even greater for women than men, a new study finds.
The fact that consistently active people gain less weight over the years may not come as a surprise. But little in the way of research evidence actually supported that notion.
Most studies on physical activity and weight have focused on exercise as a way to shed excess pounds, rather than a way to ward them off.
The new study, published in the Journal of the American Medical Association, suggests that becoming active at a young age, and then keeping it up, can indeed prevent mid-life love handles.
Researchers found that among nearly 3,600 young US adults followed for 20 years in the CARDIA study, men who were "habitually" highly active over that time put on about six fewer pounds, on average, than men who exercised consistently but at relatively low levels. They also saw their waistlines expand by about an inch less.
Among women, the most active gained 1.5 fewer inches around the middle and 13 fewer pounds.
Maintaining physical activities
"It's the maintenance of the physical activity that's the important thing," said lead researcher Dr Arlene L. Hankinson, of Northwestern University in Chicago.
"It's not so much about achieving some dramatically high activity level," Dr Hankinson said. "It's about maintaining a level of daily physical activity over time."
The team measured the subjects' typical exercise, housework and job activities using a scoring system that describes intensity and duration. It yields a total of "exercise units" that reflect a person's overall high, moderate or low activity level. It also allowed the researchers to gauge whether participants maintained a consistent activity level (regardless of specific activities) over the years.
In general, health experts recommend that adults try to get at least 30 minutes of moderate-intensity exercise e.g., brisk walking five days a week. In exercise unit terms, that would yield a moderate activity level. But whether it is enough to prevent excess weight gain over time has been unclear.
The study
The current study included 3,554 men and women who were between the ages of 18 and 30 when the study began in the mid-1980s. At the outset and periodically over the next 20 years, they reported on their typical physical activity levels.
About 46% of the men and 42% of the women were consistently active during the study period.
The researchers divided those habitual exercisers into three groups: lower, moderate and higher activity. In general, men and women who were most active and, it turned out, gained the least weight, exercised for more than the widely recommended 30-minutes-a-day.
However, Dr Hankinson's team also found benefits linked to more moderate levels of exercise.
Men who consistently got 30 minutes of exercise on five days per week gained about four fewer pounds than their less-active counterparts. Women with that activity level gained about 10 fewer pounds than women who got less exercise.
It's interesting, according to the researchers, that women seem to reap a greater benefit from regular exercise. "This is the first study to show that the association between physical activity and weight is stronger in women than men," Dr Hankinson said.
Reasons unclear
The reasons are unclear, and it could simply be related to how the study data were collected: men may be more likely than women to overestimate their activity levels, for example.
Dr Hankinson said further research should look into whether women and men really do get different weight benefits from long-term physical activity.
Even though exercise is a good weapon in the battle of the bulge, people probably should not expect to still have their 20-year-old physique at the age of 40.
In this study, even the most active men and women typically gained some weight and waistline inches over time. Some amount of middle-age spread, the researchers note, may be largely unavoidable.
(Reuters Health, Amy Norton, December 2010)
