This study examined the effects of hypohydration and moderate hyperthermia (core temperature elevation) on anaerobic exercise performance in a temperate environment.
Eight active males completed two passive heat exposure trials (180 min, 45°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 (Tc) was measured throughout the experiment.
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°C; HYP: 1.0°C) and returned to baseline within 30-60 min following similar decay curves. HYP Tc remained higher (0.4°C) than EUH throughout testing (P < 0.05), but moderate hyperthermia itself produced no independent effect on anaerobic exercise performance in either trial.
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.
1U.S. Army Research Institute of Environmental Medicine, Natick, MA; and 2Florida State University, Tallahassee, FL
Address for correspondence: Samuel N. Cheuvront, PhD, U.S. Army Research Institute of Environmental Medicine, Kansas Street, Building 42, Natick, MA 01760; E-mail: Samuel.firstname.lastname@example.org.
Submitted for publication November 2005.
Accepted for publication January 2006.