Acute glutamine supplementation does not improve 20-km self-paced cycling performance in the heat

John Owen Osborne; Ian B Stewart; Kenneth W Beagley; David N Borg; Geoffrey M Minett

doi:10.1007/s00421-019-04234-2

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Acute glutamine supplementation does not improve 20-km self-paced cycling performance in the heat

Journal article

Peer reviewed

Acute glutamine supplementation does not improve 20-km self-paced cycling performance in the heat

John Owen Osborne, Ian B Stewart, Kenneth W Beagley, David N Borg and Geoffrey M Minett

European Journal of Applied Physiology, Vol.119(11-12), pp.2567-2578

2019

DOI: https://doi.org/10.1007/s00421-019-04234-2

PMID: 31565753

Abstract

glutamine

exercise

endotoxemia

hyperthermia

inflammation

Introduction The premise of this study was to investigate the effect of acute glutamine supplementation on 20 km time trial cycling performance in the heat, neuromuscular function, inflammation and endotoxemia. Methods Twelve cyclists completed two, 20-km time trials (20TT) in 35 °C (50% relative humidity). Participants ingested either glutamine (GLUT; 0.9 g kg−1 fat-free mass) or a placebo (CON) 60 min before each 20TT. Physiological and perceptual measures were recorded during each 20TT, and neuromuscular function assessed pre- and post-exercise. Venous blood was analysed for endotoxins, markers of gut damage (inflammatory fatty acid binding protein; I-FABP) and inflammatory cytokines (interleukin-6, IL-6; tumour necrosis factor-alpha, TNF-α). Data were analysed using linear mixed models in a Bayesian framework. Results 20TT in the heat increased I-FABP and elevated inflammatory cytokines (IL-6 and TNF-α) compared to pre-exercise values but did not result in endotoxemia. Completion time was not statistically different between conditions (mean difference [95% credible interval] = 11 s [− 23, 44]). Relative to CON, GLUT did not alter any physiological or perceptual measures during the 20TT. Conclusion Glutamine supplementation does not improve 20TT performance in the heat or preserve neuromuscular function when compared to a placebo. These findings suggest that glutamine is not an ergogenic aid or prophylactic intervention for heat-induced gut damage during short-duration self-paced exercise in hot environments.

Details

Title: Acute glutamine supplementation does not improve 20-km self-paced cycling performance in the heat
Authors: John Owen Osborne (Corresponding Author) - Queensland University of Technology
Ian B Stewart (Author) - Queensland University of Technology
Kenneth W Beagley - Queensland University of Technology
David N Borg - Griffith University
Geoffrey M Minett - Queensland University of Technology
Publication details: European Journal of Applied Physiology, Vol.119(11-12), pp.2567-2578
Publisher: Springer
Date published: 2019
DOI: 10.1007/s00421-019-04234-2
ISSN: 1439-6327
PMID: 31565753
Organisation Unit: School of Health
Language: English
Record Identifier: 991112952402621
Output Type: Journal article