Does exercise increase the risk of upper respiratory tract infections?
INTRODUCTION OR BACKGROUND: Heavy exercise induces marked immunodepression, which is multifactorial in origin. Evidence showing clinical significance of this immunodepression is scarce. SOURCES OF DATA: We assessed in a systematic manner whether physical activity or intensity of exercise increase susceptibility to upper respiratory tract infections (URTI). A literature search was performed using the keywords ‘upper respiratory tract infections’, ‘athletes’, ‘exercise’ and ‘physical activity’. We considered all studies reporting of the effect of exercise, physical activity, sport and training on susceptibility to URTI. A total of 162 publications were identified and 30 studies were eligible (4 descriptive, 18 observational and 8 interventional). The 30 studies included 8595 athletes (5471 runners, 2803 swimmers) and 1798 non-athletes. AREAS OF AGREEMENT: Moderate activity may enhance immune function, whereas prolonged, high-intensity exercise temporarily impairs the immune competence. A
