It's no surprise that regular exercise, particularly brisk walking, can lower your risk of heart disease and diabetes, but did you know it may reduce the risk of catching common cold too?

Yes, researchers in the United States have carried out a study and found that exercise, like walking, for at least half-an-hour daily helps to ward off common old.

According to lead researcher Cornelia M. Ulrich of the Fred Hutchinson Cancer Research Centre in Seattle, "There's been a lot of anecdotal evidence that exercise prevents infection, and colds in particular."

In fact, the Ulrich and her team came to the conclusion after conducting a study of the effects of regular exercise on breast cancer in post-menopausal women.

Half of the 115 women involved in the study were put on a programme in which they did moderate exercise like brisk walking for 45 minutes a day, five times a week. The other group did not exercise, but participated in a weekly stretching class for the duration of the year-long research.

The team found that the women in the non-exercise group suffered from twice as many colds as those who did exercise. The protection against colds among the participants was greatest during the last three months of the trial, during which the non-exercisers had three times the risk of catching a cold.

The effects of exercise on the immune system were seen in the active group despite the fact that they managed just 30 minutes of walking a day, on average, according to the findings reported in the American Journal of Medicine.

"This suggests that when it comes to preventing colds, it's really important to stick with exercise long term," wrote Ulrich.