Snipe, RMJ and Khoo, A and Kitic, CM and Gibson, PR and Costa, RJS, The impact of exertional-heat stress on gastrointestinal integrity, gastrointestinal symptoms, systemic endotoxin and cytokine profile, European Journal of Applied Physiology, 118, (2) pp. 389-400. ISSN 1439-6319 (2018) [Refereed Article]
Copyright 2017 Springer-Verlag GmbH Germany, part of Springer Nature
Purpose: The study aimed to determine the effects of exertional-heat stress on gastrointestinal integrity, symptoms, systemic endotoxin and inflammatory responses; and assess the relationship between changes in body temperature and gastrointestinal perturbations.
Methods: Ten endurance runners completed 2 h running at 60% V02max in hot (HOT: 35 °C) and temperate (TEMP: 22 °C)ambient conditions. Rectal temperature (Tre) and gastrointestinal symptoms were recorded every 10 min during exercise. Blood samples were collected pre- and post-exercise, and during recovery to determine plasma intestinal fatty acid binding protein (I-FABP), cortisol, bacterial endotoxin and cytokine profile. Calprotectin was determined from pre- and post-exercise faecal samples. Urinary lactulose:L-rhamnose ratio was used to measure intestinal permeability.
Results: Compared with TEMP, HOT significantly increased Tre (1.4 ± 0.5 vs 2.4 ± 0.8 °C, p < 0.001), cortisol (26 vs 82%, p < 0.001), I-FABP (127 vs 432%, p < 0.001), incidence (70 vs 90%) and severity (58 counts vs 720 counts, p = 0.008) of total gastrointestinal symptoms. Faecal calprotectin and circulating endotoxin increased post-exercise in both trials (mean increase 1.5 ± 2.5 µg/g, p = 0.032, and 6.9 ± 10.3 pg/ml, p = 0.04 7, respectively), while anti-endotoxin antibodies increased 28% post-exercise in TEMP and decreased 21 % in HOT (p = 0.027). However, intestinal permeability did not differ between trials (p = 0.185). Inflammatory cytokines were greater on HOT compared to TEMP (p < 0.05). Increases in Tre were positively associated with I-FABP, IL-10, cortisol, nausea and urge to regurgitate (p < 0.05).
Conclusions: Exertional-heat stress induces a thermoregulatory strain that subsequently injures the intestinal epithelium, reduces endotoxin clearance capacity, promotes greater cytokinaemia, and development of gastrointestinal symptoms.
|Item Type:||Refereed Article|
|Keywords:||Euhydration · Running · Permeability · I-FABP · Calprotectin · Inflammation|
|Research Division:||Health Sciences|
|Research Group:||Sports science and exercise|
|Research Field:||Sports science and exercise not elsewhere classified|
|Objective Group:||Specific population health (excl. Indigenous health)|
|Objective Field:||Specific population health (excl. Indigenous health) not elsewhere classified|
|UTAS Author:||Kitic, CM (Dr Cecilia Kitic)|
|Year Published:||2018 (online first 2017)|
|Web of Science® Times Cited:||35|
|Deposited By:||Health Sciences|
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