LYMPHOCYTE FUNCTION AND CYTOKINE PRODUCTION DURING INCREMENTAL EXERCISE IN ACTIVE AND SEDENTARY MALES AND FEMALES

This study examined the effects of acute continuous incremental exerci se on lymphocyte mitogenic function and cytokine production in physica lly active and sedentary males and females. Physically active (n = 32) and sedentary (N = 32) male and female subjects were randomly assigne d to an exercise or control condition. Exercise involved a continuous incremental protocol consisting of cycling for 3 periods of 6 min at w orkrates corresponding to 55 %, 70 % and 85 % VO(2)peak. Blood samples were drawn from a venous catheter at baseline, 6 min, 12 min and 18 m in, and 2 h following completion of exercise. Relative to baseline and control condition the percentage of T (CD3(+)) and B cells (CD19(+)) significantly decreased, and the percentage of NK cells (CD3(-)CD16(+) CD56(+)) increased (p < 0.001) during each stage of the incremental ex ercise test. The proliferative response to ConA was suppressed, enhanc ed, or unchanged using 1.25 mu g/ml, 2.5 mu g/ml and 5.0 mu g/ml ConA, respectively. The in-vitro production of IL-1 and IFN-gamma increased during each workload. In contrast IL-4 production did not change duri ng exercise. The resting and exercise induced alterations in lymphocyt e function and cytokine production were independent of gender and fitn ess level, and returned to baseline 2 h into recovery. The in-vitro pr oduction of IFN-gamma and IL-4 suggests that physical activity may alt er the balance of TH1 and TH2 lymphocytes.