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.