Beat the common cold with regular exercise

Echinacea. Orange juice. Steam rooms. I've heard people swear by all kinds of strategies for avoiding the common cold, but so far the evidence remains thin for most of them. It's likely you'll get two or three colds each year whatever you do (although washing your hands regularly won't hurt).

According to a new study though, keeping fit might help you spend less time feeling ill with a cold. That might sound obvious, but previous research found that top athletes were more vulnerable to colds.

The new study followed 1,002 ordinary people for 12 weeks during fall or winter, and recorded how much time they spent ill with a cold. The researchers also asked people about their exercise habits and how they rated their fitness levels.

People who exercised more often also rated the colds they did get as milder. It might be that the people who exercised more were also younger, or ate healthier foods, or were less likely to smoke. Healthy behaviors tend to cluster together, which makes studies like this one hard to interpret. However, the researchers adjusted their results to take these factors into account, and still found that exercise cut the time people spent suffering from a cold.

The researchers think that moderate exercise might prevent colds by giving the immune system a short-term boost. This could explain why studies looking at high-level athletes have given different results: intensive training is harder on the body, and seems to weaken the immune system for a short time afterward. The study looked at ordinary people between the ages of 18 and 85, so the results might not apply to people doing regular, intensive exercise, such as top athletes or people training for a marathon.

What you need to know. Regular exercise seems to cut the amount of time people spend feeling ill with a cold. National guidelines recommend getting at least two-and-a-half hours of moderate exercise each week.

—Philip Wilson, patient editor, BMJ Group