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Individual variability in achievement of short-term heat acclimation during a fixed intensity protocol. J Therm Biol 2022; 110:103373. [DOI: 10.1016/j.jtherbio.2022.103373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 10/04/2022] [Accepted: 10/12/2022] [Indexed: 12/05/2022]
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Mündel T, Gilmour S, Kruger M, Thomson J. Reliability of a 60-min treadmill running protocol in the heat: The journal Temperature toolbox. Temperature (Austin) 2022; 10:279-286. [PMID: 37554382 PMCID: PMC10405772 DOI: 10.1080/23328940.2022.2143168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/15/2022] Open
Abstract
We determined the reliability of a 60-min treadmill protocol in the heat when spaced >4 weeks apart, longer than the test-retest duration of 1 week found in the literature. Nine unacclimated, trained males (age: 31 ± 8 y; VO2peak: 60 ± 6 ml∙kg-1∙min-1) undertook a 15 min self-paced time-trial pre-loaded with 45 min of running at 70% of individual ventilatory threshold (11.2 ± 0.3 km∙h-1) in 30 ± 1°C (53 ± 5% relative humidity). They repeated this following 40 ± 14 and 76 ± 26 days, with pre-trial standardization of diet and exercise for 48 h. When considering trial 1 as a familiarization, change in core temperature (∆Tcore) during the first 45 min (∆2.0 ± 0.2°C) between trials 2 and 3 yielded bias and 95% limits of agreement (LoA) of -0.10 ± 0.43°C, standard error of measurement (SEM) of 0.13°C and intraclass correlation coefficient (ICC) of 0.75, more reliable than measures of baseline Tcore (36.9 ± 0.2°C; LoA: -0.23 ± 0.90°C; SEM: 0.22°C; ICC: 0.03) and Tcore at 45 min during exercise (38.9 ± 0.4°C; LoA: 0.32 ± 1.12°C; SEM: 0.28°C; ICC: 0.15). The coefficient of variation (CV) between trials 2 and 3 for distance run during the 15 min time-trial was 2.1 ± 2.0% with LoA of 0.001 ± 0.253 km and SEM of 0.037 km. This protocol is reliable spaced ~5 weeks apart when considering the most commonly accepted limit of <5% CV for performance, reinforced by reliability of the ΔTcore being 0.1 ± 0.4°C.
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Affiliation(s)
- Toby Mündel
- School of Sport Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Simon Gilmour
- Fonterra Research and Development Centre, Palmerston North, New Zealand
| | - Marlena Kruger
- School of Health Sciences, Massey University, Palmerston North, New Zealand
| | - Jasmine Thomson
- Fonterra Research and Development Centre, Palmerston North, New Zealand
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Millet J, Siracusa J, Tardo-Dino PE, Thivel D, Koulmann N, Malgoyre A, Charlot K. Effects of Acute Heat and Cold Exposures at Rest or during Exercise on Subsequent Energy Intake: A Systematic Review and Meta-Analysis. Nutrients 2021; 13:nu13103424. [PMID: 34684424 PMCID: PMC8538265 DOI: 10.3390/nu13103424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 02/06/2023] Open
Abstract
The objective of this meta-analysis was to assess the effect of acute heat/cold exposure on subsequent energy intake (EI) in adults. We searched the following sources for publications on this topic: PubMed, Ovid Medline, Science Direct and SPORTDiscus. The eligibility criteria for study selection were: randomized controlled trials performed in adults (169 men and 30 women; 20–52 years old) comparing EI at one or more meals taken ad libitum, during and/or after exposure to heat/cold and thermoneutral conditions. One of several exercise sessions could be realized before or during thermal exposures. Two of the thirteen studies included examined the effect of heat (one during exercise and one during exercise and at rest), eight investigated the effect of cold (six during exercise and two at rest), and three the effect of both heat and cold (two during exercise and one at rest). The meta-analysis revealed a small increase in EI in cold conditions (g = 0.44; p = 0.019) and a small decrease in hot conditions (g = −0.39, p = 0.022) for exposure during both rest and exercise. Exposures to heat and cold altered EI in opposite ways, with heat decreasing EI and cold increasing it. The effect of exercise remains unclear.
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Affiliation(s)
- Juliette Millet
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Julien Siracusa
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Pierre-Emmanuel Tardo-Dino
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - David Thivel
- Laboratory AME2P, University of Clermont Auvergne, 63170 Aubière, France;
| | - Nathalie Koulmann
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
- Ecole du Val-de-Grâce, 1, Place Alphonse Laveran, 75230 Paris, France
| | - Alexandra Malgoyre
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Keyne Charlot
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
- Correspondence: ; Tel.: +33-(1)78-65-13-03
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Four-month operational heat acclimatization positively affects the level of heat tolerance 6 months later. Sci Rep 2020; 10:20260. [PMID: 33219295 PMCID: PMC7680124 DOI: 10.1038/s41598-020-77358-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/30/2020] [Indexed: 12/02/2022] Open
Abstract
Benefits obtained after heat acclimation/acclimatization should be completely lost after an estimated period of 6 weeks. However, this estimate is still hypothetical. We evaluate the long-term effects of heat acclimatization on the level of heat tolerance. Physiological and subjective markers of heat tolerance were assessed during a heat stress test (HST: 3 × 8-min runs outdoors [~ 40 °C and 20% RH] at 50% of their estimated speed at VO2max) performed on the 2nd day upon arrival to the desert military base in the United Arab Emirates after a first day of mostly passive exposure to heat. Among the 50 male French soldiers, 25 partook in a 4-month military mission in countries characterized by a hot environment ~ 6 months prior to the study (HA). The other 25 participants were never heat acclimatized (CT). Rectal temperature (p = 0.023), heart rate (p = 0.033), and perceived exertion (p = 0.043) were lower in the HA than CT group at the end of HST. Soldiers who experienced a former 4-month period of natural heat acclimatization very likely had a higher level of heat tolerance during exercise in the heat, even 6 months after returning from the previous desert mission, than that of their non-acclimatized counterparts.
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