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Abstract

Increasing temperature and exercise disrupt tight junctions of the gastrointestinal tract although thecontribution of environmental temperature to intestinal damage when exercising is unknown. Thisstudy investigated the effect of two different environmental temperatures on intestinal damage whenexercising at the same relative intensity. Participants (n=12M, mean±SD:81.98±7.95kg, 182.6±7.4cm)completed randomised cycling trials (45min, 70%V̇ O2max) in 30°C/40%RH and 20°C/40%RH. A subsetof participants (n=5) also completed a seated passive trial (30°C/40%RH). Rectal temperature andthermal sensation (TSS) were recorded during each trial and venous blood samples collected preandpost-trial for the analysis of intestinal fatty acid-binding protein (I-FABP) level as a marker ofintestinal damage. V̇ O2 was similar between 30°C and 20°C exercise trials, as intended (p=0.94). IFABPincreased post-exercise in 30°C (pre-exercise:585±188pgmL-1, post-exercise:954±411pgmL1)and 20°C (pre-exercise:571±175 pgmL-1, post-exercise:852±317pgmL-1) (p<0.0001) but themagnitude of damage was similar between temperatures (p=0.58). There was no significant increasein I-FABP concentration following passive heat exposure (p=0.59). Rectal temperature increasedduring exercise trials (p<0.001), but not the passive trial (p=0.084). TSS increased more whenexercising in 30°C compared to 20°C (p<0.001). There was an increase in TSS during the passiveheat trial (p=0.03). Intestinal damage, as measured by I-FABP, following exercise in the heat wassimilar to when exercising in a cooler environment at the same relative intensity. Passive heatexposure did not increase I-FABP. It is suggested that when exercising in conditions of compensableheat stress, the increase in intestinal damage is predominantly attributable to the exercisecomponent, rather than environmental conditions.

Item Type:	Article
Authors/Creators:	Sheahen, BL and Fell, JW and Zadow, EK and Hartley, TF
Keywords:	intestinal damage, heat stress
Journal or Publication Title:	Applied Physiology, Nutrition and Metabolism
Publisher:	N R C Research Press
ISSN:	1715-5320
Copyright Information:	Copyright the Authors 2018.
Related URLs:	Google Scholar: Fell, JW UTAS Profile: Fell, JW UTAS Profile: Zadow, EK UTAS Profile: Hartley, TF
Item Statistics:	View statistics for this item

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