If the gym makes you feel lethargic and going for walks isn't excitable enough, try getting on to a bicycle each day for about 30 minutes. New research has found that women who cycle for half an hour each day can control their weight even during their 30s and 40s.

The analysis was based on the second Harvard Nurses' Health Study that tracked 116,608 lady nurses who periodically fill out questionnaires about their health, weight, diet and behavior. It was found that brisk walking also had the same impact on slim, overweight and obese women, though slow walking was of little use to the latter two categories of women.

The survey results, which were published in latest issue of Archives of Internal Medicine, were also based upon the weight change and behavior of the nurses from the year 1989 to 2005. The study attempted to isolate the effects of exercise while the researchers themselves controlled for other obesity risk factors.

It was found that women who had a more active life and increased physical activities like brisk walking or bicycling for 30 minutes a day during the 16-year period of the study were able to maintain their weight and even lost a few pounds. However, those who only did slow walking as exercise did not lose any weight.

And women, who reduced their bicycling time over a pre-defined period, actually gained more than four pounds on an average.

Researchers associated with the project have warned that the effects of bicycling would be felt only through a sustained 30 minute per day spell and not if one takes to the bicycle for five minutes a day. Anne C. Lusk, a research fellow at the Harvard School of Public Health, who authored the paper said the study had suggestive evidence that bicycling was beneficial to women.