Physical effort-induced changes in immune parameters.

Physical stress induces changes in immune system parameters; these changes depend on effort schedule and are influenced by customary training. The mechanisms whereby they take place are not fully elucidated: sympathetic activation-mediated mobilization of cells of lymphoid organs, including the spleen, has been suggestedWe studied exercise-induced changes (20′ of cycloergometer test conducted up to 804% of maximal expected heart rate) in white blood cells (WBC), lymphocyte subsets, plasma catecholamine and cortisol levels in three groups of subjects: swimmers, untrained controls and splenectomized individuals. Physical exercise induced increase of WBC and significant changes in the percentage of most investigated lymphocyte subsets (NK, CD3+, CD4+, CD8+ and CD4/CD8 ratio), except for DR+ cells. No changes occurred in the percentage of CD14+ cells. Norepinephrine (NE) levels increased after effort, while epinephrine (E) and cortisol levels were unchanged. Splenectomized patients displayed similar effort-in...