Riding a bicycle helps women keep their weight down in middle-age, a new study finds. Even small increases in time spent biking — of 5 min. or less per day — are associated with less weight gain as women age.
The data come from the ongoing Nurses’ Health Study II, which involves 116,608 women, who have been answering periodic questionnaires about their medical history, lifestyle and health-related behaviors since 1989.
For the current study, published this week in the Archives of Internal Medicine, researchers tracked women’s weight changes and exercise habits for 16 years starting in 1989, when the women were between the ages of 25 and 42.
Overall, the women gained weight as they aged — nearly 21 lbs, on average. But those who reported having increased their activity levels by 30 min. per day between 1989 and 2005 ended up gaining significantly less weight than their more sedentary peers. The finding applied to increases in moderately intense exercise, including biking, brisk walking, jogging, swimming and hiking — but not to slow walking (less than 3 miles per hour). The benefits of exercise were strongest in women who were overweight or obese at baseline.
The authors of the study looked further at the impact of bicycling, which has not typically been analyzed separately from walking or other activities in past studies — and has not been studied much in women. The current study showed that the longer women biked, the less likely they were to gain weight. Compared with normal-weight women who didn’t bike at all, women who biked at least four hours per week were 26% less likely to gain 5% or more of their initial body weight.
Again, the benefit was greater in overweight and obese women, who were 47% less likely to have increased their weight by 5% or more by the end of the study if they biked four hours a week, compared with women who didn’t ride.
But the authors note that relatively few women in their study biked for any substantial amount of time; many more women reported walking for physical activity. That preference could simply be a matter of marketing: multiple studies have shown the benefits of walking, which has been described as the “near perfect form of exercise,” the authors write, but few have investigated the advantages of biking.
It’s probably also true that many women lack a comfortable biking environment. Indeed, America’s car-centric culture doesn’t exactly encourage biking — not nearly as much as, say, in the Netherlands, where 22% of the population walks to work and 27% commutes by bike. In comparison, 9% of the U.S. population walks for commuting, and 0.5% bikes, according to background information in the study.
But if biking is just as good as brisk walking for curbing weight gain in middle age, women might consider doing it more — especially in place of driving, the authors suggest:
Unlike discretionary gym time, bicycling could replace time spent in a car for necessary travel of some distance to work, shops or school as activities of daily living. Bicycling could then be an unconscious form of exercise because the trip’s destination, and not the exercise, could be the goal.
The government recommends two-and-a-half hours of moderate intensity aerobic exercise per week, or one hour and 15 min. of vigorous exercise, for good health. (Click here for the government’s physical activity guidelines for Americans.)
