Sex Differences in Exercise-Induced Effects on Respiratory Infection and Immune Function

A physically active lifestyle has health benefits, including enhanced vaccination responses, improved neutrophil and macrophage function, increased T cell proliferative capacity, lower numbers of senescent T cells, and lower levels of inflammatory cytokines. Therefore, exercise or physical activity is effective for preventing and treating chronic diseases. A more robust immune response is generally thought to be exerted in females than males in response to various challenges. Sex hormones in both sexes have been suggested as mediators of immune function, but research on this topic has not been designed with a sex-specific lens. The authors reviewed and summarized the experimental and clinical evidence in the available literature linking exercise, immune function, and risk of upper respiratory infections, as well as associated mechanisms. Collectively, the available literature indicates that moderate exercise improves immune function and risk for upper respiratory infections in both sexes. In contrast, prolonged and high-intensity exercise temporarily impairs immune responses and upper respiratory infection risk at a higher degree in females than males. Therefore, moderate exercise and activity may enhance immune function regardless of sex, whereas prolonged and high-intensity exercise temporarily impairs immune responses, predominantly in females more than their male counterparts.