Heat Acclimation by Postexercise Hot-Water Immersion: Reduction of Thermal Strain During Morning and Afternoon Exercise-Heat Stress After Morning Hot-Water Immersion

in International Journal of Sports Physiology and Performance
Restricted access

Purchase article

USD  $24.95

Student 1 year subscription

USD  $107.00

1 year subscription

USD  $142.00

Student 2 year subscription

USD  $203.00

2 year subscription

USD  $265.00

Purpose: Recommendations state that to acquire the greatest benefit from heat-acclimation, the clock time of heat-acclimation sessions should match that of expected exercise-heat stress. It remains unknown if adaptations by postexercise hot-water immersion (HWI) demonstrate time-of-day-dependent adaptations. Thus, the authors examined whether adaptations following postexercise HWI completed in the morning were present during morning and afternoon exercise-heat stress. Methods: Ten males completed an exercise-heat stress test commencing in the morning (9:45 AM) and afternoon (2:45 PM; 40 min; 65% of maximal oxygen uptake treadmill run) before and after heat-acclimation. The 6-d heat-acclimation intervention involved a daily 40-min treadmill run (65% of maximal oxygen uptake) in temperate conditions followed by ≤40-min HWI (40°C; 6:30–11:00 AM). Results: Adaptations by 6-d postexercise HWI in the morning were similar in the morning and afternoon. Reductions in resting rectal temperature (Tre) (AM −0.34°C [0.24°C], PM −0.27°C [0.23°C]; P = .002), Tre at sweating onset (AM −0.34°C [0.24°C], PM −0.31°C [0.25°C]; P = .001), and end-exercise Tre (AM −0.47°C [0.33°C], PM −0.43°C [0.29°C]; P = .001), heart rate (AM −14 [7] beats·min−1, PM −13 [6] beats·min−1; P < .01), rating of perceived exertion (P = .01), and thermal sensation (P = .005) were not different in the morning compared with the afternoon. Conclusion: Morning heat acclimation by postexercise HWI induced adaptations at rest and during exercise-heat stress in the morning and midafternoon.

The authors are with the College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom.

Mee (j.a.mee@bangor.ac.uk) is corresponding author.
  • 1.

    Périard JD, Racinais S, Sawka MN. Adaptations and mechanisms of human heat acclimation: applications for competitive athletes and sports. Scand J Med Sci Sports. 2015;25:20–38. doi:10.1111/sms.12408

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2.

    Lorenzo S, Halliwill JR, Sawka MN, Minson CT. Heat acclimation improves exercise performance. J Appl Physiol. 2010;109(4):1140–1147. PubMed ID: 20724560 doi:10.1152/japplphysiol.00495.2010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3.

    Gonzalez RR, Gagge AP. Warm discomfort and associated thermoregulatory changes during dry, and humid-heat acclimatization. Isr J Med Sci. 1976;12(8):804–807. PubMed ID: 977289

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4.

    Frank A, Belokopytov M, Moran D, Shapiro Y, Epstein Y. Changes in heart rate variability following acclimation to heat. J Basic Clin Physiol Pharmacol. 2001;12(1):19–32. PubMed ID: 11414505 doi:10.1007/s00421-014-2935-5

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5.

    Taylor NS. Human heat adaptation. Compr Physiol. 2014;4(1):325–365. PubMed ID: 24692142 doi:10.1002/cphy.c130022

  • 6.

    Cable NT, Drust B, Gregson WA. The impact of altered climatic conditions and altitude on circadian physiology. Physiol Behav. 2007;90(2–3):267–273. doi:10.1016/j.physbeh.2006.09.002

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7.

    Chalmers S, Esterman A, Eston R, Bowering KJ, Norton K. Short-term heat acclimation training improves physical performance: a systematic review, and exploration of physiological adaptations and application for team sports. Sports Med. 2014;44(7):971–988. PubMed ID: 24817609 doi:10.1007/s40279-014-0178-6

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8.

    Beaudin AE, Clegg ME, Walsh ML, White MD. Adaptation of exercise ventilation during an actively-induced hyperthermia following passive heat acclimation. Am J Physiol Regul Integr Comp Physiol. 2009;297(3):605–614. PubMed ID: 19494169 doi:10.1152/ajpregu.90672.2008

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9.

    Patterson MJ, Stocks JM, Taylor NA. Whole-body fluid distribution in humans during dehydration and recovery, before and after humid-heat acclimation induced using controlled hyperthermia. Acta Physiol. 2014;210:899–912. doi:10.1111/apha.12214

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10.

    Shido O, Sugimoto N, Tanabe M, Sakurada S. Core temperature and sweating onset in humans acclimated to heat given at a fixed daily time. Am J Physiol. 1999;276:R1095–R1101. PubMed ID: 10198390

    • Search Google Scholar
    • Export Citation
  • 11.

    Sakurada S, Shido O, Sugimoto N, Fujikake K, Nagasaka T. Changes in hypothalamic temperature of rats after daily exposure to heat at a fixed time. Pflugers Arch Eur J Physiol. 1994;429:291–293. doi:10.1007/BF00374326

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 12.

    Shido O, Yoneda Y, Nagasaka T. Shifts in the hypothalamic temperature of rats acclimated to direct internal heat load with different schedules. J Therm Biol. 1991;16(5):267–271. doi:10.1016/0306-4565(91)90015-t

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13.

    Maruyama M, Hara T, Katakura M, et al. Contribution of the suprachiasmatic nucleus to the formation of a time memory for heat exposure in rats. J Physiol Sci. 2007;57(2):107–114. PubMed ID: 17341320 doi:10.2170/physiolsci.RP014506

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14.

    Garrett AT, Goosens NG, Rehrer NJ, Rehrer NG, Patterson MJ, Cotter JD. Induction and decay of short-term heat acclimation. Eur J Appl Physiol. 2009;107(6):659–670. PubMed ID: 19727796 doi:10.1007/s00421-009-1182-7

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15.

    Zurawlew MJ, Walsh NP, Fortes MB, Potter C. Post-exercise hot water immersion induces heat acclimation and improves endurance exercise performance in the heat. Scand J Med Sci Sports. 2016;26(7):745–754. doi:10.1111/sms.12638

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16.

    Tyler CJ, Reeve T, Hodges GJ, Cheung SS. The effects of heat adaptation on physiology, perception and exercise performance in the heat: a meta-analysis. Sports Med. 2016;46(11):1699–1724. doi:10.1007/s40279-016-0538-5

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 17.

    World Medical Association. World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. 2013;310(20):2191.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18.

    Aschoff J. Circadian control of body temperature. J Therm Biol. 1983;8:143–147. doi:10.1016/0306-4565(83)90094-3

  • 19.

    Fortes MB, Di Felice U, Dolci A, et al. Muscle-damaging exercise increases heat strain during subsequent exercise heat stress. Med Sci Sports Exerc. 2013;45(10):1915–1924. PubMed ID: 23559121 doi:10.1249/MSS.0b013e318294b0f8

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20.

    Armstrong L. Hydration assessment techniques. Nutr Rev. 2005;63(3):S40–S54. doi:10.1111/j.1753-4887.2005.tb00153.x

  • 21.

    Borg G. Perceived exertion as an indicator of somatic stress. Scand J Rehabil Med. 1970;2(2):92–98. PubMed ID: 5523831

  • 22.

    Hollies N, Goldman R. Psychological scaling in comfort assessment. In: Hollies NRS, Goldman RFG, eds. Clothing Comfort: Interaction of Thermal, Ventilation, Construction, and Assessment Factors. Ann Arbor, MI: Ann Arbor Science; 1977:107–120.

    • Search Google Scholar
    • Export Citation
  • 23.

    Cheuvront SN, Chinevere TD, Ely BR, et al. Serum S-100β response to exercise-heat strain before and after acclimation. Med Sci Sports Exerc. 2008;40(8):1477–1482. PubMed ID: 18614943 doi:10.1249/MSS.0b013e31816d65a5

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24.

    Ramanathan NL. A new weighting system for mean surface temperature of the human body. J Appl Physiol. 1964;19:531–533. PubMed ID: 14173555 doi:10.1152/jappl.1964.19.3.531

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25.

    Cheuvront S, Bearden S, Kenefick R, et al. A simple and valid method to determine thermoregulatory sweating threshold and sensitivity. J Appl Physiol. 2009;107(1):69–75. PubMed ID: 19423839 doi:10.1152/japplphysiol.00250.2009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26.

    Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol. 1974;37(2):247–248. PubMed ID: 4850854 doi:10.1152/jappl.1974.37.2.247

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27.

    Cohen J. Statistical Power Analysis for the Behavioral Sciences. New York, NY: Routledge Academic; 1988.

  • 28.

    Sugimoto N, Shido O, Sakurada S. Thermoregulatory responses of rats acclimated to heat given daily at a fixed time. J Appl Physiol. 1995;78(5):1720–1724. PubMed ID: 7649905 doi:10.1152/jappl.1995.78.5.1720

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29.

    Gibson OR, Mee JA, Tuttle JA, Taylor L, Watt PW, Maxwell NS. Isothermic and fixed intensity heat acclimation methods induce similar heat adaptation following short and long-term timescales. J Therm Biol. 2015;49–50:55–65. PubMed ID: 25774027 doi:10.1016/j.jtherbio.2015.02.005

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30.

    Hill DW, Leiferman JA, Lynch NA, Dangelmaier BS, Burt SE. Temporal specificity in adaptations to high-intensity exercise training. Med Sci Sports Exerc. 1998;30(3):450–455. PubMed ID: 9526893 doi:10.1097/00005768-199803000-00017

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 105 106 6
Full Text Views 13 13 0
PDF Downloads 4 4 0