Postexercise thermal and cardiovascular responses following fast and slow heating exercise protocols

Par Conseil national de recherches du Canada

Auteur	Rechercher : Kenny, Glen P.; Rechercher : Wright, Heather E.; Rechercher : Friesen, Brian J.
Format	Texte, Allocution
Conférence	Experimental Biology 2011, Apr. 9th-13th, 2011, Washington, D.C.
Résumé	Exercise-induced hyperthermia can result in significant cardiovascular and thermoregulatory disturbances which can persist for a prolonged period. However, it is unclear if this response differs as a function of the time to reach hyperthermia. Therefore, we compared cardiovascular and thermoregulatory responses of subjects rendered hyperthermic by either a slow heating (SH) or fast heating (FH) exercise protocol performed in the heat (40°C). On separate days, 7 subjects either walked (4 mph, 2% grade, SH) or ran (7.5 mph, 2% grade, FH) on a treadmill until rectal temperature (Tre) increased to 39.5°C. Subjects then rested in the upright seated position in thermoneutral conditions (30°C) until Tre returned to 38.0°C. Heart rate (HR) and mean arterial pressure (MAP) were assessed continuously. Change in plasma volume (ΔPV) from baseline rest was measured at end of recovery. The time to reach Tre of 39.5°C was significantly longer during SH (76.5±6.5 min) compared to FH (35.5±3.3 min, p<0.05). However, the time to reach the Tre recovery of 38.0°C was significantly greater during FH compared to SH (82.5±9.2 vs. 56.2±6.5 min, p<0.05). Despite a longer recovery during FH, a similar reduction in MAP (FH:−9.6±1.7 vs. SH: −10.1±3.4 mmHg) was observed at end-recovery which was paralleled by similar elevations in HR (FH:83±2 vs. SH:87±5 bpm). Further, ΔPV was also similar between conditions (FH: −5.1±1.9 vs. SH: −5.8±2.8%) albeit reduced from end-exercise values (FH:9.0±1.1% vs. SH:11.8±1.5%,p<0.05). Different exercise-intensity ramping protocols performed to a similar level of thermal strain influence core temperature recovery time but not the level of cardiovascular strain.
Date de publication	2011-04-12
Maison d’édition	Federation of American Societies for Experimental Biology
Dans	The FASEB Journal 25, nº Supplement 1, 105.3.
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	23001381
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Identificateur de l’enregistrement	867c98bd-2f0a-4cbb-875d-9039ccc5db80
Enregistrement créé	2017-01-31
Enregistrement modifié	2020-03-03

Date de modification :: 2024-07-27