Exercise, Cytokines, and Lymphocytes

Abstract

Recent studies suggest that the beneficial effects of exercise may, in part, be mediated by exercise-induced changes in cytokine responses, which, in turn, have several effects, including effects on metabolism and on the cellular immune system (1). The mechanisms underlying exercise-induced immune changes also include neuroendocrinological factors (2). Thus, nutritional intervention may influence the immune response to exercise on several levels. When the immune system is studied at rest in trained vs. untrained humans, few differences are found. However, the so-called natural immunity mediated by natural killer (NK) cells is slightly enhanced in trained subjects (2). Whereas little changes are found in trained vs. untrained subjects at rest, an acute bout of exercise induces dramatic immune system changes. Regarding lymphocyte changes (number and function), the findings are highly consistent. The intensity and duration of the exercise affect the magnitude of changes, whereas the mode of exercise has little influence (2). However, if the exercise includes an eccentric component and thereby muscle damage and cell infiltration, this has some effect, which is described later. In general, both moderate and intense exercise (even if only for a few minutes) induce mobilization of lymphocytes to the blood. After intense exercise (more than 70% of VO2max) of long duration (more than 45 min), immune impairment occurs (2). The nature of these changes, the mechanisms of action, and the influence of nutritional intervention are described in this chapter.KeywordsEccentric ExerciseCarbohydrate IngestionStrenuous ExerciseIntense ExerciseGlutamine SupplementationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.