Engaging in regular aerobic activity (1 to 5 times per week) could reduce the risk of respiratory infections by approximately 50% and decrease the severity of symptoms by 32% to 41%.

noli's read

This advice is based on a body of solid scientific literature regarding the impact of exercise on the immune system. Observational studies and meta-analyses, notably published in the 'British Journal of Sports Medicine', confirm that moderate and regular physical activity is associated with an improved immune response and a reduction in the incidence of upper respiratory tract infections. The proposed mechanism relies on the temporary increase of circulating immune cells and a long-term reduction in systemic inflammation. However, it is important to note that these data primarily come from observational studies, which show a correlation but do not prove direct and isolated causality. Furthermore, researchers often highlight a 'J'-shaped curve: while moderate exercise is protective, extreme and prolonged training without sufficient recovery can temporarily weaken immune defenses. The claim is therefore well-supported, while remaining a statistical generalization that depends on individual context and the intensity of the effort.

the sources

1. 1Campbell JP, Turner JE 2018