Immunoglobulin is an important soluble mediator of host defense against bacterial and viral infections. Serum Ig level do not change with acute exercise or after moderate exercise training. Small in serum Ig levels are explained by a combination of diurnal or seasonal effects and hemoconcentration occuring during exercise. However, recent reports show low serum Ig level in athletes durings prolonged periods of intensive exercise training, compared with clinical norms. Production of serum antibodyies to specific antigens in animal model finds to enhanced following moderate training, but the effects of intensive training on specific antibodies are not yet known. In contrast to serum Ig, the concentration of salivary IgA and secretory IgA levels in elite athletes are decreses acutely after intensive exercise and over prolonged periods of intensive training. The mechanisms related the decresed serum Ig and secretory IgA levels not currently known but may involve physical and psychological factors resulting from intensive daily exercise. It has been suggested that the scretory IgA related exercise may be one mechanism responsible for high incidence of URI among athletes who train intensibly on a daily over prolonged periods of time. In futures research, The relationship between physical and psychological stressors, the neuroendocrine responses to exercise traninig, and their combined influences on immune function among athletes, as well as in the popualce who is encoutaged to exercise for health benefits should be needed to understand.