Induction and decay of short-term heat acclimation

  • Andrew T. Garrett
  • Niels G. Goosens
  • Nancy G. Rehrer
  • Mark J. Patterson
  • James D. Cotter
Original Article


The purpose of this work was to investigate adaptation and decay from short-term (5-day) heat acclimation (STHA). Ten moderately trained males (mean ± SD age 28 ± 7 years; body mass 74.6 ± 4.4 kg; \( \dot{V}_{{{\text{O}}_{ 2{\text{peak}}} }} \) 4.26 ± 0.37 l min−1) underwent heat acclimation (Acc) for 90-min on 5-days consecutively (T a = 39.5°C, 60% RH), under controlled hyperthermia (rectal temperature 38.5°C). Participants completed a heat stress test (HST) 1 week before acclimation (Acc), then on the 2nd and 8th day (1 week) following Acc (T a = 35°C, 60% RH). Seven participants completed HSTs 2 and 3 weeks after Acc. HST consisted of 90-min cycling at 40% peak power output before an incremental performance test. Rectal temperature at rest (37.1 ± 0.4°C) was not lowered by Acc (95% CI −0.3 to 0.2°C), after 90-min exercise (38.6 ± 0.5°C) it reduced 0.3°C (−0.5 to −0.1°C) and remained at this level 1 week later (−0.5 to −0.1°C), but not two (0.1°C −0.4 to 0.5°C; n = 7) or 3 weeks. Similarly, heart rate after 90-min exercise (146 ± 21 b min−1) was reduced (−13: −6 to −20 b min−1) and remained at this level after 1 week (−13: −6 to −20 b min−1) but not two (−9: 6 to −23 b min−1; n = 7) or 3 weeks. Performance (746 s) increased 106 s: 59 to 152 s after Acc and remained higher after one (76 s: 31 to 122) but not two (15 s: −88 to 142 s; n = 7) or 3 weeks. Therefore, STHA (5-day) induced adaptations permitting increased heat loss and this persisted 1 week but not 2 weeks following Acc.


Acclimation Induction Adaptation Decay 



Special thanks are given to the participants in this study and the technical expertise provided by Mrs R. McKay and Miss D. Wilson. This work was supported by grants from the Australian Defence Science Technology Organisation and School of Physical Education, University of Otago, New Zealand.


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Andrew T. Garrett
    • 1
    • 3
  • Niels G. Goosens
    • 1
  • Nancy G. Rehrer
    • 1
  • Mark J. Patterson
    • 2
  • James D. Cotter
    • 1
  1. 1.School of Physical EducationUniversity of OtagoDunedinNew Zealand
  2. 2.Defence Science Technology Organisation (DSTO)MelbourneAustralia
  3. 3.Division of Sport, Health and Exercise, School of Life ScienceUniversity of HertfordshireHatfieldUK

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