Influence of Exercise Mode and Carbohydrate on the Immune Response to Prolonged Exercise

The influence of exercise mode and 6% carbohydrate (C) versus placebo (P) beverage ingestion on lymphocyte proliferation, natural killer cell cytotoxicily (NKCA), Interleukin (IL)-1s production, and hormonal responses to 2.5 hr of intense running and cycling (~75% V˙O2max) was measured in 10 triathletes serving as their own controls. The C versus P condition (but not exercise mode) resulted in higher plasma glucose concentrations, lower plasma cortisol concentrations, reduced poslexercise lymphocytosis and NKCA, and a lessened T-cell reduction during recovery. No condition or mode effects were observed for concanavalin A and phytohemagglutinin-induced lymphocyte proliferation. Significant mode (but not condition) effects were observed for lipopolysaccharide-induced IL-1s production over time. However, when expressed per monocyte, the mode effect was abolished and a sustained suppression in IL-1 s/monocyte was observed in all sessions throughout recovery. These data indicate that carbohydrate ingestion sig...