Exercise and Training: Influences on Cytotoxicity, Interleukin-1, Interleukin-2 and Receptor Structures

Abstract

Exercise responses are discussed with particular reference to the functional system involving interleukin-1, interleukin 2 and cytotoxicity. Prolonged endurance exercise causes an increase in plasma levels of interleukin-1, possibly as a response to muscle injuries, but plasma interleukin-2 levels generally fall. The latter change probably reflects stronger binding, consequent upon increased expression of p70-75 receptors for IL-2, and changes in the distribution or activity of target cells; IL-1 secretion may enhance the responsiveness of peripheral blood mononuclear cells, but prostaglandin secretion decreases their IL-2 production. Moderate exercise increases the cytolytic action of NK cells, but there is a prolonged fall of cytolytic activity after exhausting or psychologically stressful exercise; again these responses probably reflect altered IL-2 levels or receptor expression. Appropriately graded training reduces the adverse immune reactions associated with challenging exercise. Cross-sectional comparison and training experiments both show an increased expression of p70-75 IL-2 receptors on the NK cells of active individuals. Moreover, moderate training reduces the exercise-induced suppression of IL-2 production. However, training that is pursued to the level of staleness, nutrient deficiency or muscle damage has a negative impact upon both the production of interleukins and the leukocyte response. Coaches must thus gauge training programs to optimize not only physiological function but also immune responses.

Key words

Exercise - training - over-training - staleness - NK cytotoxicity - interleukins - cytokines.