EXERCISE AND THE IMMUNE SYSTEM

Abstract

The effects of exercise on the immune system are under investigation in recent years. Immune system responses that occur following acute and chronic exercise are different. The effects of exercise on immune system functions depend on many variables such as exercise intensity, duration, severity and individuals’ physical fitness level. Immune system functions increase when performing mild or moderate intensity exercise, but in contrast they are suppressed following prolonged high intensity exercise. Following high intensity exercise; lymphocyte concentration, proliferation ability of the cells, moderate cytotoxic activity and immunoglobulin production all decrease. During the period of immune impairment that lasts for 3-72 hours following exercise, which is referred to as the “open window” period; microbial agents, especially viruses may invade the host and infections may occur. Therefore, to defend athletes from the negative effects of high intensity exercise, especially during the periods of intense training and racing, it is important to provide adequate food and rest. Furthermore, because of diminishment of the cytotoxic capacity in blood during the recovery period after exercise, one should pay attention to infections. It seems to be preferable for people who exercise for health, to perform moderate intensity exercise of the type that does not cause stress.