YOU’VE probably heard the advice: One of the best things you can do to keep healthy — especially as cold and flu season creeps up — is stay physically active.

This folk wisdom has been around for ages, but until recently, researchers did not have much data to support the idea. Now, scientists studying risk factors related to Covid-19 have turned up some preliminary evidence about the link between regular exercise and better immune defences against disease.

When researchers reviewed 16 studies of people who stayed physically active during the pandemic, they found that working out was associated with a lower risk of infection as well as a lower likelihood of severe Covid-19. The analysis, published last month (Aug) in the British Journal of Sports Medicine, has generated a lot of enthusiasm among exercise scientists, who say the findings could lead to updated guidelines for physical activity and healthcare policy that revolves around exercise as medicine.