20 minutes of exercise can ward off flu

Intense physical activity for even 20 minutes everyday can protect you against several illnesses, including flu, research has shown.

The findings suggest that at least 100 cases of flu per 1,000 people could be prevented just by increasing the intensity of exercise.

The researchers estimate that two-and-a-half hours of vigorous exercise a week cuts the risk of flu-like illnesses by around 10 percent.

The figures come from Flusurvey, the online flu study run by the London School of Hygiene & Tropical Medicine based on responses from 4,800 participants.

However, moderate exercise appears to have little effect on rates of flu-like illness; which means the intensity is all important, the researchers said.

"We're really interested in the preliminary findings around fitness activity and flu-like illness, as exercise is something that everyone can do to reduce your chance of having flu," said Alma Adler of the London School of Hygiene & Tropical Medicine.

"We need to treat this result cautiously as these are preliminary findings. However, they are consistent with findings for other conditions and really show the health benefits of exercise."