A new research suggests that doing at least two and a half hours of vigorous exercise each week cuts the chance of developing flu.

Around 4,800 people took part in this year’s online Flu Survey, run by the London School of Hygiene and Tropical Medicine.

Moderate exercise did not appear to have a protective effect, the researchers said.

Overall, flu rates have been relatively low this winter.

Doing at least two and a half hours of vigorous exercise each week cuts the chance of developing flu

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 research findings suggest 100 cases of flu per 1,000 people could be prevented just by engaging in vigorous exercise.

Researchers 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.

Children also appear to have had lower levels of flu-like illness than last year with just 5% reporting symptoms this flu season compared with 7.9% last year.