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Pre-exercise hyperhydration delays dehydration and improves endurance capacity during 2 h of cycling in a temperate climate

Goulet, Eric D. B and Rousseau, Stéphane F and Lamboley, C. R and Plante, Gérard E and Dionne, Isabelle J (2008) Pre-exercise hyperhydration delays dehydration and improves endurance capacity during 2 h of cycling in a temperate climate. Journal of Physiological Anthropology, 27 (5). pp. 263-271. ISSN 1880-6791

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Abstract

Whether the use of pre-exercise hyperhydration could improve the performance of athletes who do not hydrate sufficiently during prolonged exercise is still unknown. We therefore compared the effects of pre-exercise hyperhydration and pre-exercise euhydration on endurance capacity, peak power output and selected components of the cardiovascular and thermoregulatory systems during prolonged cycling. Using a randomized, crossover experimental design, 6 endurance-trained subjects underwent a pre-exercise hyperhydration (26 ml of water·kg body mass−1 with 1.2 g glycerol·kg body mass−1) or pre-exercise euhydration period of 80 min, followed by 2 h of cycling at 65% maximal oxygen consumption (VO2max) (26–27°C) that were interspersed by 5, 2-min intervals performed at 80% VO2max. Following the 2 h cycling exercise, subjects underwent an incremental cycling test to exhaustion. Pre-exercise hyperhydration increased body water by 16.1±2.2 ml·kg body mass−1. During exercise, subjects received 12.5 ml of sports drink·kg body mass−1. With pre-exercise hyperhydration and pre-exercise euhydration, respectively, fluid ingestion during exercise replaced 31.0±2.9% and 37.1±6.8% of sweat losses (p>0.05). Body mass loss at the end of exercise reached 1.7±0.3% with pre-exercise hyperhydration and 3.3±0.4% with pre-exercise euhydration (p<0.05). During the 2 h of cycling, pre-exercise hyperhydration significantly decreased heart rate and perceived thirst, but rectal temperature, sweat rate, perceived exertion and perceived heat-stress did not differ between conditions. Pre-exercise hyperhydration significantly increased time to exhaustion and peak power output, compared with pre-exercise euhydration. We conclude that pre-exercise hyperhydration improves endurance capacity and peak power output and decreases heart rate and thirst sensation, but does not reduce rectal temperature during 2 h of moderate to intense cycling in a moderate environment when fluid consumption is 33% of sweat losses.

Item Type: Article
Additional Information:

Online ISSN: 1880-6805

Uncontrolled Keywords: ResPubID22013. fluid overloading, exercise capacity, moderate ambient condition, heart rate, rectal temperature
Subjects: FOR Classification > 1106 Human Movement and Sports Science
Faculty/School/Research Centre/Department > Institute of Sport, Exercise and Active Living (ISEAL)
Depositing User: VUIR
Date Deposited: 25 Apr 2012 23:19
Last Modified: 04 Mar 2015 04:50
URI: http://vuir.vu.edu.au/id/eprint/7978
DOI: 10.2114/jpa2.27.263
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Citations in Scopus: 12 - View on Scopus

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