No effect of moderate hypohydration or hyperthermia on anaerobic exercise performance

Purpose: This study examined the effects of hypohydration and moderate hyperthermia (core temperature elevation) on anaerobic exercise performance in a temperate environment. Methods: Eight active males completed two passive heat exposure trials (180 min, 45 degrees C, 50% rh) with (EUH) and without (HYP) fluid replacement. A single 15-s Wingate anaerobic test (WAnT) was used to assess anaerobic performance (peak power, mean power, and fatigue index) before (-180 min) and again at three time points after passive heat exposure to include immediately (0 min), 30 min, and 60 min after in a temperate environment (22 C). Rectal temperature (T.) was measured throughout the experiment. Results: HYP reduced body mass (2.7 +/- 0.7%) (P < 0.05) but had no effect on any WAnT performance measure. Passive heat exposure elicited moderate hyperthermia in both trials (EUH: 0.6 degrees C; HYP: 1.0 degrees C) and returned to baseline within 30-60 min following similar decay curves. HYP T, remained higher (0.4 degrees C) than EUH throughout testing (P < 0.05), but moderate hyperthermia itself produced no independent effect on anaerobic exercise performance in either trial. Conclusions: This study demonstrates that neither moderate HYP nor the moderate hyperthermia accompanying HYP by passive heat exposure affect anaerobic exercise performance in a temperate environment.