Flu risk 'cut by vigorous exercise'
Moderate exercise did not appear to have a protective effect.
A new study suggests that doing at least two and a half hours of vigorous exercise each week cuts the chance of developing flu.
Around four thousand eight hundred people took part in the Flu Survey, run by the London School of Hygiene and Tropical Medicine that said moderate exercise did not appear to have a protective effect.
One of the questions people must answer when they register, as well as their age, if they are around children and if they have been vaccinated, is how many hours of "vigorous exercise" they do each week, such as running, fast cycling or competitive sports, ranging from none to more than five hours.
They are then asked to log in each week and note how they are feeling, and whether or not they have any flu-like symptoms.
The researchers say their findings suggest 100 cases of flu per 1,000 people could be prevented just by engaging in vigorous exercise.
They also said this year's survey found some of the lowest reports of flu-like illness in recent years.
Over the winter flu season, only 4.7% of reports were positive for flu- like symptoms compared with 6% last year.