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) b everage ingestion on lymphocyte proliferation, natural killer cell cytotoxi city (NKCA), Interleukin (IL)-1 beta production, and hormonal responses to 2.5 hr of intense running and cycling (similar to 75% (V) over dot O(2)max) was measured in 10 triathletes serving as their own controls. The C versus P condition (but not exercise mode) resulted in higher plasma glucose conc entrations, lower plasma cortisol concentrations, reduced postexercise lymp hocytosis and NKCA, and a lessened T-cell reduction during recovery. No con dition or mode effects were observed for concanavalin A and phytohemaggluti nin-induced lymphocyte proliferation. Significant mode (but not condition) effects were observed for lipopolysaccharide-induced IL-I beta production o ver time. However, when expressed per monocyte, the mode effect was abolish ed and a sustained suppression in IL-1 beta/monocyte was observed in all se ssions throughout recovery. These data indicate that carbohydrate ingestion significantly affects plasma glucose and cortisol concentrations, blood ly mphocyte counts, and NKCA, whereas exercise mode has no effect on these par ameters.