Cortisol and interleukin-6 responses during intermittent exercise in two different hot environments with equivalent WBGT

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1080/15459624.2012.666467
Auteur	Rechercher : Wright, Heather E.; Rechercher : Mclellan, Tom M.; Rechercher : Stapleton, Jill M.; Rechercher : Hardcastle, Stephen G.; Rechercher : Kenny, Glen P.
Format	Texte, Article
Sujet	body heat content; calorimetry; core temperature; heat stress; neuroendocrine and immune responses; work
Résumé	Blood marker concentrations such as cortisol (COR) and interleukin (IL)-6 are commonly used to evaluate the physiological strain associated with work in the heat. It is unclear, however, if hot environments of an equivalent thermal stress, as defined by a similar wet bulb globe temperature (WBGT), result in similar response patterns. This study examined markers of neuroendocrine (COR) and immune (IL-6) responses, as well as the cardiovascular and thermal responses, relative to changes in body heat content measured by whole-body direct calorimetry during work in two different hot environments with equivalent WBGT. Eight males performed a 2-hr heavy intermittent exercise protocol (six 15-min bouts of cycling at a constant rate of metabolic heat production (360W) interspersed by 5-min rest periods) in Hot/Dry (46°C, 10% relative humidity [RH]) and Warm/Humid (33°C, 60% RH) conditions (WBGT ∼ 29°C). Whole-body evaporative and dry heat exchange, change in body heat content (ΔH(b)), rectal temperature (T(re)), and heart rate were measured continuously. Venous blood was obtained at rest (PRE) and the end of each exercise bout for the measurement of changes in plasma volume (PV), plasma protein (an estimate of plasma water changes), COR, and IL-6. Ratings of perceived exertion and thermal sensation were measured during the last minute of each exercise bout. No differences existed for ΔH(b), heart rate, T(re),%ΔPV, plasma protein concentration, perceptual strain (thermal sensation, perceived exertion), and COR between the Hot/Dry and Warm/Humid conditions. IL-6 exhibited an interaction effect (p = 0.041), such that greater increases were observed in the Hot/Dry (Δ = 1.61 pg·mL(-1)) compared with the Warm/Humid (Δ = 0.64 pg·mL(-1)) environment. These findings indicate that work performed in two different hot environments with equivalent WBGT resulted in similar levels of thermal, cardiovascular, and perceptual strain, which support the use of the WBGT stress index. However, the greater IL-6 response in the Hot/Dry requires further research to elucidate the effects of different hot environments and work intensities.
Date de publication	2012-02-21
Maison d’édition	Taylor and Francis
Dans	Journal of Occupational and Environmental Hygiene 9, nº 4 : 269–279.
Langue	anglais
Publications évaluées par des pairs	Oui
Publication du CNRC	Cette publication n’est pas du CNRC Ce sont des publications qui ont été rédigées par un auteur du CNRC, mais avant que celui-ci soit employé du CNRC.
Numéro NPARC	23001228
Exporter la notice	Exporter en format RIS
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Identificateur de l’enregistrement	ee06e1df-5808-4ed7-9baf-da7eee8a12b1
Enregistrement créé	2017-01-06
Enregistrement modifié	2020-04-21

Date de modification :: 2024-11-08