Many studies have indicated that regular moderate exercises are beneficial in the prevention of infectious diseases. However, epidemiological studies demonstrate that endurance athletes are at increased risk of upper respiratory tract infection (URTI) after heavy training and/or competition. Neutrophil is an effective phagocyte and is considered to be an important part of innate immunity. An impaired neutrophil microbicidal capacity may increase the susceptibility to infection in stressed athletes. Therefore, the purposes of this review were to describe the relationship between stress hormones and neutrophil function, how a single bout and/or repeated bouts of exercise affected neutrophil degranulation and oxidative burst capacity, and how the effect of carbohydrate supplementation influenced neutrophil function.