Effect of glycerol hyperhydration before exercise in trained triathletes on endurance performance and cardiovascular and thermoregulatory responses

Abstract

This experimental project determined the effect of glycerol hyperhydration in 4 trained male triathletes on endurance performance and cardiovascular and thermoregulatory responses. For this purpose, the subjects received, using a randomized, double-blind and crossover protocol, either a glycerol (1.2 g glycerol/kg/bodyweight (BW) with 18 ml/kg/BW of aspartame-flavored juice plus 8 ml/kg/BW of distilled water) or a placebo solution (aspartame-flavored juice and water only) over an 80 min period, 40 min before exercise, then performed 2 h of cycling at 65% of maximal oxygen consumption (VO[subscript 2] max), which was immediately followed by an endurance performance test to exhaustion. All trials were conducted at 25[degrees Celsius], 38-42% relative humidity (RH). During exercise, subjects consumed a 6% sports drink (SD) solution at a rate of 166 ml every 20 min, up to min 100. Preliminary results suggest that glycerol hyperhydration could attenuate dehydration better than water hyperhydration during a cycling exercise at 65% VO[subscript 2] max in a thermoneutral climate, which could improve core temperature, but not HR. With respect to the endurance performance test, the comparison of the mean of each group reveals that glycerol hyperhydration did not increase time to exhaustion."--Résumé abrégé par UMI.