Does Dehydration Affect the Adaptations of Plasma Volume, Heart Rate, Internal Body Temperature, and Sweat Rate During the Induction Phase of Heat Acclimation?

in Journal of Sport Rehabilitation
Restricted access

Purchase article

USD  $24.95

Student 1 year subscription

USD  $74.00

1 year subscription

USD  $99.00

Student 2 year subscription

USD  $141.00

2 year subscription

USD  $185.00

Clinical Scenario: Exercise in the heat can lead to performance decrements and increase the risk of heat illness. Heat acclimation refers to the systematic and gradual increase in exercise in a controlled, laboratory environment. Increased duration and intensity of exercise in the heat positively affects physiological responses, such as higher sweat rate, plasma volume expansion, decreased heart rate, and lower internal body temperature. Many heat acclimation studies have examined the hydration status of the subjects exercising in the heat. Some of the physiological responses that are desired to elicit heat acclimation (ie, higher heart rate and internal body temperature) are exacerbated in a dehydrated state. Thus, euhydration (optimal hydration) and dehydration trials during heat acclimation induction have been conducted to determine if there are additional benefits to dehydrated exercise trials on physiological adaptations. However, there is still much debate over hydration status and its effect on heat acclimation. Clinical Question: Does dehydration affect the adaptations of plasma volume, heart rate, internal body temperature, skin temperature, and sweat rate during the induction phase of heat acclimation? Summary of Findings: There were no observed differences in plasma volume, internal body temperature, and skin temperature following heat acclimation in this critically appraised topic. One study found an increase in sweat rate and another study indicated greater changes in heart rate following heat acclimation with dehydration. Aside from these findings, all 4 trials did not observe statistically significant differences in euhydrated and dehydrated heat acclimation trials. Clinical Bottom Line: There is minimal evidence to suggest that hydration status affects heat acclimation induction. In the studies that met the inclusion criteria, there were no differences in plasma volume concentrations, internal body temperature, and skin temperature. Strength of Recommendation: Based on the Oxford Centre for Evidence-Based Medicine Scale, Level 2 evidence exists.

The authors are with the Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT.

Sekiguchi (yasuki.sekiguchi@uconn.edu) 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(suppl 1):20–38. PubMed ID: 25943654 doi:

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

    Armstrong LE, Millard-Stafford M, Moran DS, Pyne SW, Roberts WO. American College of Sports Medicine position stand. Exertional heat illness during training and competition. Med Sci Sports Exerc. 2007;39(3):556–572. PubMed ID: 17473783 doi:

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

    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. PubMed ID: 27106556 doi:

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

    Daanen HAM, Racinais S, Périard JD. Heat acclimation decay and re-induction: a systematic review and meta-analysis. Sports Med. 2018;48(2):409–430. PubMed ID: 29129022 doi:

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

    Schleh MW, Ruby BC, Dumke CL. Short term heat acclimation reduces heat stress, but is not augmented by dehydration. J Therm Biol. 2018;78:227–234. PubMed ID: 30509641 doi:

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6.

    Pethick WA, Murray HJ, McFadyen P, Brodie R, Gaul CA, Stellingwerff T. Effects of hydration status during heat acclimation on plasma volume and performance. Scand J Med Sci Sports. 2019;29(2):189–199. PubMed ID: 30317666 doi:

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

    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(4):899–912. PubMed ID: 24330400 doi:

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

    Garrett AT, Creasy R, Rehrer NJ, Patterson MJ, Cotter JD. Effectiveness of short-term heat acclimation for highly trained athletes. Eur J Appl Physiol. 2012;112(5):1827–1837. PubMed ID: 21915701 doi:

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

    Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377–390. PubMed ID: 17277604 doi:

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

    Armstrong LE, Maresh CM, Gabaree CV, et al. Thermal and circulatory responses during exercise: effects of hypohydration, dehydration, and water intake. J Appl Physiol. 1997;82(6):2028–2035. PubMed ID: 9173973 doi:

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11.

    Neal RA, Massey HC, Tipton MJ, Young JS, Corbett J. Effect of permissive dehydration on induction and decay of heat acclimation, and temperate exercise performance. Front Physiol. 2016;7:564. PubMed ID: 27932993 doi:

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

    Garrett AT, Goosens NG, Rehrer NJ, et al. Short-term heat acclimation is effective and may be enhanced rather than impaired by dehydration. Am J Hum Biol. 2014;26(3):311–320. PubMed ID: 24469986 doi:

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 314 314 91
Full Text Views 18 18 5
PDF Downloads 13 13 4