T helper cell cytokine profiles after endurance exercise

Abstract

Endurance exercise can cause immunosuppression and increase the risk of upper respiratory illness. The present study examined changes in the secretion of T helper (Th) cell cytokines after endurance exercise. Ten highly trained road cyclists [meanᓅM: age 24.2ᱮ7 years; height 1.82ᰮ02?m; body mass 73.8Ხ0?kg; peak oxygen uptake 65.9Ხ3?mL/(kg孩n)] performed 2?h of cycling exercise at 90% of the second ventilatory threshold. Peripheral blood mononuclear cells were isolated and stimulated with phytohemagglutinin. Plasma cortisol concentrations and the concentration of Th1/Th2/Th17 cell cytokines were examined. Data were analyzed using both traditional statistics and magnitude-based inferences. Results revealed a significant decrease in plasma cortisol at 4-24?h postexercise compared with pre-exercise values. Qualitative analysis revealed postexercise changes in concentrations of plasma cortisol, IL-2, TNF, IL-4, IL-6, IL-10, and IL-17A compared with pre-exercise values. A Th1/Th2 shift was evident immediately postexercise. Furthermore, for multiple cytokines, including IL-2 and TNF (Th1), IL-6 and IL-10 (Th2), and IL-17 (Th17), no meaningful change in concentration occurred until more than 4?h postexercise, highlighting the duration of exercise-induced changes in immune function. These results demonstrate the importance of considering "clinically" significant versus statistically significant changes in immune cell function after exercise.