Blunting the rise in body temperature reduces muscle glycogenolysis during exercise in humans

Abstract

To examine the effect of blunting the rise in body temperature on exercise metabolism, seven endurance-trained men cycled for 40 min at 65% of maximal oxygen consumption (V̇(O2)max) in an environmental chamber at either 20°C and 20% relative humidity (RH) (T20) or 3°C and ~ 50% RH (T3). The trials were conducted in random order at least 1 week apart. Mean oxygen comsumption (V̇(O2)) during exercise was not different when comparing the two trials. In contrast, the mean respiratory exchange ratio (RER) was lower (P < 0.05) at T20 compared with T3. Heart rate, rectal temperature and plasma catecholamines were higher (P < 0.05) during exercise at T20 compared with T3, as was post-exercise muscle..