US study says regular cycling is best way for women to fight the flab

Less weight gain seen among those who maintained or increased bike riding over 16-year period

by Simon_MacMichael   June 29, 2010  

Female Cyclist, London. (copyright Simon MacMichael)JPG

An academic study in the United States has established that riding a bike or walking briskly are the key forms of exercise that pre-menopausal women can take to help avoid putting on weight.

While that may not be headline-grabbing news in itself – it’s pretty universally accepted that exercise is beneficial in fighting the flab – the study is of particular interest because of its focus on cycling and comparison of its effects with other forms of physical activity such as walking.

Moreover, the study found that the effects of regular cycling were more pronounced among those women who were at the upper end of the weight scale in 1989, when the data being analysed began, and that cycling with the aim of getting to a destination, be that the shops or a workplace, for example, could be more beneficial than forms of exercise that have no other purpose.

“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," the authors of the study, which was led by Anne C Lusk, Ph.D of the Harvard School of Medicine in Boston, said. "Bicycling could then be an unconscious form of exercise because the trip's destination, and not the exercise, could be the goal," they added.

The study’s findings have been published in the June 28 issue of the Archives of Internal Medicine, with the authors explaining: "To our knowledge, research has not been conducted on bicycle riding and weight control in comparison with walking. Our objective was to assess the association between bicycle riding and weight control in premenopausal women."

Highlighting the scale of the problem, the study cited background research that demonstrated that two in three adults (66%) in the US are classified as overweight or obese; furthermore, one in six children and adolescents (16%) are overweight with a further one in three (34%) are at risk of being overweight.

The background research also found that only one in 200 (0.5%) of the US commuting population ride bicycles, and only one in four (23%) of those are women.
The researchers studied 18,414 women who had taken part in the Nurses' Health Study II, an ongoing study of more than 116,600 U.S. female nurses aged 25 to 42 when it started in 1989. They concentrated on those women who were premenopausal through 2005, assessing their weight change between 1989 and 2005.

The baseline study in 1989 established that half the women (50%) spent time walking slowly, two in five (39%) said that they spent some time walking briskly and around one in two (48%) claimed that they rode a bicycle some of the time.
In 2005, it was found that participants on average stated that they spent more time walking briskly, some time walking slowly, but the least time was spent cycling.

The study also found that they spent five times longer on average sitting at home than doing all forms of exercise combined.

Researchers established that those who did not ride a bike in 1989 but were doing so by 2005, even for as little as five minutes a day, showed less likelihood to put on weight, with increased benefit found the longer they spent cycling; conversely, women who had been cycling more in 1989 than they were in 2005 put on more weight.

They also discovered that women of normal weight who spent four hours a week or more cycling in 2005 had a lower chance of having put on more than 5% of their baseline body weight in 1989, when the survey commenced, compared to those who did not ride a bike.

The authors say that the findings demonstrate “a significant relationship between increased time spent bicycling in 2005 and odds of weight gain.”

"The results appeared to be stronger in women with excess baseline weight compared with lean women,” they continue. “The mean [average] weight gain was the smallest in women who engaged in four hours a week or more of bicycling compared with women who bicycled for less time."

They added that "the benefits of brisk walking, bicycling and other activities were significantly stronger among overweight and obese women compared with lean women, whereas slow walking continued to show no benefit even among overweight and obese women."