The effect of cycling in the heat on gastrointestinal-induced damage and neuromuscular fatigue

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

doi:10.1007/s00421-019-04172-z

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The effect of cycling in the heat on gastrointestinal-induced damage and neuromuscular fatigue

Journal article

Peer reviewed

The effect of cycling in the heat on gastrointestinal-induced damage and neuromuscular fatigue

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

European Journal of Applied Physiology, Vol.119(8), pp.1829-1840

2019

DOI: https://doi.org/10.1007/s00421-019-04172-z

PMID: 31175438

Abstract

thermoregulation

endotoxemia

cycling

central fatigue

hyperthermia

Purpose This study investigated the effect of exercise in the heat on neuromuscular function, gastrointestinal damage, endotoxemia and inflammatory cytokines. Methods Eight male cyclists completed two 60 min cycling trials in both hot (HOT 34.5 ± 0.1 °C and 53 ± 1% relative humidity) and temperate environments (CON 20.2 ± 0.3 °C and 55 ± 3% relative humidity). The cycling task comprised of alternating 3 min intervals at a moderate-vigorous intensity (50% and 70% of maximum power output; Pmax) for 30 min, followed by 30 min at moderate intensity (40–50% Pmax). Neuromuscular function was assessed at pre-, post-exercise and 60 min post-exercise. Circulating levels of endotoxins, inflammatory cytokines and markers of gut permeability and damage were also collected at these time points. Heart rate, core temperature, skin temperature, perceived exertion, thermal sensation and comfort were also measured. Results Post-exercise voluntary activation of HOT (87.9% [85.2, 90.8]) was statistically lower (mean difference − 2.5% [− 4.5, − 0.5], d = 2.50) than that of CON (90.5% [87.8, 93.2]). The HOT trial resulted in statistically elevated (+ 69%) markers of gastrointestinal damage compared to CON (mean difference 0.424 ng mL−1 [0.163, 0.684, d = − 3.26]), although this was not observed for endotoxin, other inflammatory markers, or gastrointestinal permeability. Conclusions This research provides evidence that short-duration cycling in the heat results in sub-optimal neuromuscular activation and increased expression of gastrointestinal damage markers, without a simultaneous elevation in circulating endotoxins or pro-inflammatory cytokines.

Details

Title: The effect of cycling in the heat on gastrointestinal-induced damage and neuromuscular fatigue
Authors: John Owen Osborne (Corresponding Author) - Queensland University of Technology
Ian B Stewart - Queensland University of Technology
Kenneth W Beagley - Queensland University of Technology
Geoffrey M Minett - Queensland University of Technology
Publication details: European Journal of Applied Physiology, Vol.119(8), pp.1829-1840
Publisher: Springer
Date published: 2019
DOI: 10.1007/s00421-019-04172-z
ISSN: 1439-6327
PMID: 31175438
Organisation Unit: School of Health
Language: English
Record Identifier: 991112952502621
Output Type: Journal article