Carbohydrate Supplementation and the Lymphocyte Proliferative Response to Long Endurance Running

This randomized, double-blind, placebo-controlled study examined the influence of 6 % carbohydrate ingestion on hormonal and lymphocyte proliferative responses (5 total samples over 9 hours) to 2.5 h of high-intensity running by 30 experienced marathon runners. The T-cell response differed between groups, with the placebo group exhibiting a greater increase immediately post-run and greater decrease at 3 h of recovery. No group differences were observed for Con A-, PHA-, or PWM-induced lymphocyte proliferation. However, when PHA was adjusted per T-cell, group differences were observed, highlighted by a decrease in the placebo group immediately post-run. Glucose and Cortisol responses differed between groups, with glucose lower and Cortisol higher in the placebo group immediately post-run. Post-run glucose correlated negatively with post-run Cortisol (r = - 0.670, P < 0.001) and epinephrine (r = - 0.540, P = 0.002). Post-run Cortisol also correlated negatively with total lymphocytes and T-cells at 1.5 hours (r = - 0.429, P = 0.018 and r = - 0.424, P = 0.019, respectively) and 3 hours (r = - 0.566, P = 0.001 and r = - 0.523, P = 0.003, respectively) of recovery. The pre- to post-run change in glucose correlated to the same changes in PHA/T-cell (r = 0.456, P = 0.011). The data support an interactive effect of carbohydrate ingestion on plasma glucose and Cortisol. The data support an interactive effect of carbohydrate ingestion on plasma glucose and Cortisol, T-cell trafficking, and cell-adjusted PHA-induced lymphocyte proliferation following long endurance running.