The Sweating and Core Temperature Response to Compensable and Uncompensable Heat Stress Following Heat Acclimation
Notice bibliographique
Résumé
While a greater maximal sweat rate following heat acclimation has been suggested to mitigate the rise in core temperature during uncompensable heat stress, it remains unclear whether heat acclimation will alter the core temperature response to compensable heat stress wherein heat balance is attainable. Thus, the primary aim of the present study was to evaluate the influence of complete heat acclimation on sweating and core temperature response to exercise in a compensable and uncompensable environment. A total of 8 (6 males, 2 females) unacclimated individuals were recruited. On separate days, participants exercised at a fixed rate of heat production (450 W) for 45‐mins of compensable heat stress (CHS; 37°C, 30% RH) and 60‐min of uncompressible heat stress (UCHS; 37°C, 60% RH) before and after heat acclimation. Core temperature [esophageal (T es ) and rectal (T re )], local sweat rate of the arm (LSR arm ) and back (LSR back ), and whole body sweat loss (WBSL) were measured during experimental trials. Heat acclimation included an 8‐wk aerobic training intervention followed by 10 consecutive days of up to 90 minutes of treadmill walking in hot and humid conditions (38°C, 65% RH). Prior to CHS or UCHS, resting absolute T es and T re were lower following heat acclimation (T es : 36.6±0.2°C; T re : 36.8±0.1°C) relative to unacclimated (T es : 36.9±0.2°C, P=0.002; T re : 37.1±0.2°C, P=0.003). During CHS, the change in T es and T re were similar following heat acclimation (ΔT es : 0.4±0.1°C; ΔT re : 0.7±0.1°C) compared to unacclimated (ΔT es : 0.4±0.2°C, P=0.72; ΔT re : 0.7±0.1°C, P=0.61). Cumulative WBSL during CHS was marginally greater with acclimation (557±40 g) relative to unacclimated (494±59 g, P=0.01). Despite no difference in LSR back following 45‐min of CHS with or without heat acclimation (P=0.94), stead‐state LSR arm was slightly higher with acclimation (0.75±0.16 mg/cm 2 /min) compared to unacclimated (0.61±0.15 mg/cm 2 /min, P<0.001). In contrast, the change in T es and T re during UCHS was significantly smaller following heat acclimation (ΔT es : 0.7±0.2°C; ΔT re : 0.9±0.2°C) relative to an unacclimated state (ΔT es : 1.1±0.3°C, P=0.04; ΔT re : 1.1±0.2°C, P<0.001). WBSL was far greater during UCHS post‐heat acclimation (913±126 g) in comparison to prior to acclimation (671±83 g, P<0.001). Further, end‐exercise LSR back and LSR arm were higher post‐heat acclimation (LSR back : 1.48±0.28 mg/cm 2 /min; LSR arm : 1.20±0.33 mg/cm 2 /min) relative to pre‐acclimation (LSR back : 1.21±0.26, P<0.001; LSR arm : 0.91±0.26 mg/cm 2 /min, P<0.001) during UCHS. Taken together, the core temperature response to compensable heat stress is similar irrespective of acclimation status, despite marginal greater whole‐body sweat rates. However, the large increases local and whole body sweat rate following heat acclimation clearly mitigated the rise in core temperature during uncompensable heat stress. Support or Funding Information This research was supported by a Discovery Grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada (#386143‐2010, held by O.J.). N.R. was supported by an NSERC Postgraduate Scholarship‐Doctoral and a University of Ottawa Excellence Scholarship. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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Prédiction machine sur la base complète
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Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».