Whole body heat loss is reduced in older males during short bouts of intermittent exercise

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DOI	Trouver le DOI : https://doi.org/10.1152/ajpregu.00157.2013
Auteur	Rechercher : Larose, Joanie; Rechercher : Wright, Heather E.; Rechercher : Stapleton, Jill; Rechercher : Sigal, Ronald J.; Rechercher : Boulay, Pierre; Rechercher : Hardcastle, Stephen; Rechercher : Kenny, Glen P.
Format	Texte, Article
Sujet	aging; calorimetry; evaporative heat loss; thermal transients
Résumé	Studies in young adults show that a greater proportion of heat is gained shortly following the start of exercise and that temporal changes in whole body heat loss during intermittent exercise have a pronounced effect on body heat storage. The consequences of short-duration intermittent exercise on heat storage with aging are unclear. We compared evaporative heat loss (HE) and changes in body heat content (ΔHb) between young (20-30 yr), middle-aged (40-45 yr), and older males (60-70 yr) of similar body mass and surface area, during successive exercise (4 × 15 min) and recovery periods (4 × 15 min) at a fixed rate of heat production (400 W) and under fixed environmental conditions (35 °C/20% relative humidity). HE was lower in older males vs. young males during each exercise (Ex1: 283 ± 10 vs. 332 ± 11 kJ, Ex2: 334 ± 10 vs. 379 ± 5 kJ, Ex3: 347 ± 11 vs. 392 ± 5 kJ, and Ex4: 347 ± 10 vs. 387 ± 5 kJ, all P less than 0.02), whereas HE in middle-aged males was intermediate to that measured in young and older adults (Ex1: 314 ± 13, Ex2: 355 ± 13, Ex3: 371 ± 13, and Ex4: 365 ± 8 kJ). HE was not significantly different between groups during the recovery periods. The net effect over 2 h was a greater ΔHb in older (267 ± 33 kJ; P = 0.016) and middle-aged adults (245 ± 16 kJ; P = 0.073) relative to younger counterparts (164 ± 20 kJ). As a result of a reduced capacity to dissipate heat during exercise, which was not compensated by a sufficiently greater rate of heat loss during recovery, both older and middle-aged males had a progressively greater rate of heat storage compared with young males over 2 h of intermittent exercise.
Date de publication	2013-09-15
Maison d’édition	American Physical Society
Dans	AJP : Regulatory, Integrative and Comparative Physiology 305, nº 6 : R619–R629.
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	23001207
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Identificateur de l’enregistrement	9ebf65a3-3476-425f-80e9-a061dac3f1d0
Enregistrement créé	2017-01-05
Enregistrement modifié	2020-06-02

Date de modification :: 2025-01-15