Exercise and immune function: effect of ageing and nutrition

Strenuous exercise is followed by lymphopenia, neutrophilia, impaired natur al immunity, decreased lymphocyte proliferative responses to mitogens, a lo w level of secretory immunoglobulin A in saliva, but high circulating level s of pro- and anti-inflammatory cytokines. These exercise-induced immune ch anges may provide the physiological basis of altered resistance to infectio ns. The mechanisms underlying exercise-induced immune changes are multifact orial and include neuroendocrinological and metabolic mechanisms. Nutrition al supplementation with glutamine abolishes the exercise-induced decline in plasma glutamine, but does not influence post-exercise immune impairment. However, carbohydrate loading diminishes most exercise effects of cytokines , lymphocyte and neutrophils. The diminished neutrophilia and elastase (EC 3.4.21.37) responses to eccentric exercise in elderly subjects were enhance d to levels comparable with those of young subjects by fish oil or vitamin E supplements. However, although vitamin C supplementation may diminish the risk of contracting an infection after strenuous exercise, it is not obvio us that this effect is Linked to an effect of vitamin C on exercise-induced immune changes. In conclusion, it is premature to make recommendations reg arding nutritional supplementation to avoid post-exercise impairment of the immune system.