Body heat storage during intermittent work in hot–dry and warm–wet environments

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1139/h2012-053
Auteur	Rechercher : Stapleton, Jill M.; Rechercher : Wright, Heather E.; Rechercher : Hardcastle, Stephen G.; Rechercher : Kenny, Glen P.
Format	Texte, Article
Sujet	heat stress; thermal strain; threshold limit values; calorimetry; body heat content; core temperature
Résumé	We examined heat balance using an American Conference of Governmental Industrial Hygienists threshold limit value allocated exercise protocol in hot-dry (HD; 46 °C, 10% relative humidity (RH)) and warm-wet (WW; 33 °C, 60% RH) environments of equivalent WBGT (29 °C) for different clothing ensembles. Whole-body heat exchange and changes in body heat content (ΔH(b)) were measured using simultaneous direct whole-body and indirect calorimetry. Eight males performed six 15-min cycling periods at a constant rate of metabolic heat production (360 W) interspersed by 5-min rest periods for six experimental trials: HD and WW environments for a seminude control (CON), modified work uniform (MWU, moisture permeable top and work pants), and standard work uniform (SWU, work coveralls and cotton undergarments). Whole-body evaporative and dry heat exchange, rectal temperature (T(re)), and heart rate were measured continuously. The cumulative ΔH(b) during the 2 h intermittent exercise protocol was similar between HD and WW environments for each of the clothing ensembles (CON, 387 ± 55 vs. 435 ± 49 kJ; MWU, 485 ± 58 vs. 531 ± 61 kJ; SWU, 585 ± 74 vs. 660 ± 54 kJ, respectively). Similarly, no differences in T(re) (CON, 37.67 ± 0.07 vs. 37.48 ± 0.08 °C; MWU, 37.73 ± 0.08 vs. 37.53 ± 0.09 °C; SWU, 38.01 ± 0.09 vs. 37.94 ± 0.05 °C) or heat rate (CON, 93 ± 3 vs. 84 ± 3 beats·min⁻¹; MWU, 102 ± 5 vs. 95 ± 9 beats·min⁻¹; SWU, 119 ± 8 vs. 110 ± 9 beats·min⁻¹) were observed at the end of the 2 h intermittent exercise protocol in HD vs. WW environments, respectively. We showed similar levels of thermal and cardiovascular strain for intermittent work performed in high heat stress conditions of varying environmental conditions but similar WBGT.
Date de publication	2012-06-06
Maison d’édition	NRC Research Press
Dans	Applied Physiology, Nutrition, and Metabolism 37, nº 5 (6 juin 2012) : 840–849.
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	23001227
Exporter la notice	Exporter en format RIS
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Identificateur de l’enregistrement	49fa6d72-56d6-463a-b0b0-9c8c5775702a
Enregistrement créé	2017-01-06
Enregistrement modifié	2022-07-06

Date de modification :: 2024-07-27