Can Vigorous Exercise Reduce Flu Risk?

Doing at least two and a half hours of vigorous exercise a week could reduce your chances of experiencing a flu-like illness by around 10%, an online flu study has suggested. Around 4,800 people have participated in this year’s online Flusurvey, run by the London School of Hygiene and Tropical Medicine.

The Flusurvey findings suggest that 100 cases of flu per 1,000 people could be prevented just by engaging in vigorous exercise that leads to sweating or hard breathing, such as running, cycling and playing competitive sports. Researchers found moderate exercise, such as gentle jogging or walking, did not appear to have a protective effect.

Woman performing press-ups outdoors

Other findings from Flusurvey showed some of the lowest reports of flu-like illness in recent times. Over the winter flu season, only 4.7% of reports were positive for the onset of flu-like symptoms, compared with 6% last year. Children also appear to have had lower levels of flu-like illness with just 5% reporting symptoms this flu season compared with 7.9% last year. Flusurvey researchers suggest that the flu season this year may have been curbed by the lack of flu among young people; children have been identified as being the biggest spreaders of flu.

The annual UK Flusurvey, now in its fifth year, is an online system for measuring flu trends and uniquely collects data directly from the public through a weekly online questionnaire. The data is supplied to Public Health England’s national flu surveillance programmes, providing data which is missed through current surveillance as many people affected by flu do not visit their doctor or local hospital. Every year, more questions are added to the annual Flusurvey to try and track as much information as possible about who does and who does not fall ill with the 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, ranging from none to more than five hours. Participants are then asked to log in each week and note how they are feeling, and whether or not they have any flu-like symptoms.

Feet running on the open road

Dr Alma Adler, of the London School of Hygiene and Tropical Medicine, 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. 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”.

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

“Although many people have dodged the flu bullet this winter, flu can occur at any time, so taking advantage of the better weather is a great opportunity to get out and get fit to ward off flu this spring.”

Exercise can be a great preventative and can ward off a number of health conditions. However, if flu or respiratory illness strikes: working out while sick can do more harm than good and could weaken the immune system.


Lee Cain

Lee Cain

Writer, Tutor and Experienced Fitness Professional

Lee has over 20 years’ experience in the health and fitness industry and has performed multiple roles, including physical training instructor, strength and conditioning coach, lecturer, writer, tutor, assessor and verifier for vocational qualifications. He has a passion for all things exercise, with his key specialisms being strength and performance-based training....
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