Heart rate variability during exertional heat stress : effects of heat production and treatment

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1007/s00421-013-2804-7
Auteur	Rechercher : Flouris, Andreas D.; Rechercher : Bravi, Andrea; Rechercher : Wright-Beatty, Heather E.; Rechercher : Green, Geoffrey; Rechercher : Seely, Andrew J.; Rechercher : Kenny, Glen P.
Format	Texte, Article
Sujet	Exercise-induced hyperthermia; EHS; Heart rate variability; HRV; Core temperature; Hyperthermia
Résumé	Purpose We assessed the efficacy of different treatments (i.e., treatment with ice water immersion vs. natural recovery) and the effect of exercise intensities (i.e., low vs. high) for restoring heart rate variability (HRV) indices during recovery from exertional heat stress (EHS). Methods Nine healthy adults (26 ± 3 years, 174.2 ± 3.8 cm, 74.6 ± 4.3 kg, 17.9 ± 2.8 % body fat, 57 ± 2 mL·kg·−1 min−1 peak oxygen uptake) completed four EHS sessions incorporating either walking (4.0–4.5 km·h−1, 2 % incline) or jogging (~7.0 km·h−1, 2 % incline) on a treadmill in a hot-dry environment (40 °C, 20–30 % relative humidity) while wearing a non-permeable rain poncho for a slow or fast rate of rectal temperature (Tre) increase, respectively. Upon reaching a Tre of 39.5 °C, participants recovered until Tre returned to 38 °C either passively or with whole-body immersion in 2 °C water. A comprehensive panel of 93 HRV measures were computed from the time, frequency, time–frequency, scale-invariant, entropy and non-linear domains. Results Exertional heat stress significantly affected 60/93 HRV measures analysed. Analyses during recovery demonstrated that there were no significant differences between HRV measures that had been influenced by EHS at the end of passive recovery vs. whole-body cooling treatment (p > 0.05). Nevertheless, the cooling treatment required statistically significantly less time to reduce Tre (p less than 0.001). Conclusions While EHS has a marked effect on autonomic nervous system modulation and whole-body immersion in 2 °C water results in faster cooling, there were no observed differences in restoration of autonomic heart rate modulation as measured by HRV indices with whole-body cold-water immersion compared to passive recovery in thermoneutral conditions.
Date de publication	2014-01-05
Maison d’édition	Springer
Dans	European Journal of Applied Physiology 114, nº 4 : 785–792.
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	23001214
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Identificateur de l’enregistrement	13de8cee-ce12-4c68-8848-6e33438105df
Enregistrement créé	2017-01-05
Enregistrement modifié	2020-04-22

Date de modification :: 2024-07-27