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Induction and decay of short-term heat acclimation

Cotter, James D.; Patterson, Mark J.; Rehrer, Nancy G.; Goosens, Niels G.; Garrett, Andrew T.


James D. Cotter

Mark J. Patterson

Nancy G. Rehrer

Niels G. Goosens

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Dr Andrew Garrett
Senior Lecturer in Exercise and Environmental Physiology


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; _VO2peak 4.26 ± 0.37 l min-1) underwent heat acclimation (Acc) for 90-min on 5-days consecutively (Ta = 39.5C, 60% RH), under controlled hyperthermia (rectal temperature 38.5C). Participants completed a heat stress test (HST) 1 week before acclimation (Acc), then on the 2nd and 8th day (1 week) following Acc (Ta = 35C, 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 ± 0.4C) was not lowered by Acc (95% CI -0.3 to 0.2C), after 90-min exercise (38.6 ± 0.5C) it reduced 0.3C (-0.5 to -0.1C) and remained at this level 1 week later (-0.5 to -0.1C), but not two (0.1C -0.4 to 0.5C; 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.

Journal Article Type Article
Publication Date 2009-12
Journal European Journal of Applied Physiology
Print ISSN 1439-6319
Electronic ISSN 1439-6327
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 107
Issue 6
Pages 659-670
APA6 Citation Cotter, J. D., Patterson, M. J., Rehrer, N. G., Goosens, N. G., & Garrett, A. T. (2009). Induction and decay of short-term heat acclimation. European journal of applied physiology, 107(6), 659-670. doi:10.1007/s00421-009-1182-7
Keywords Acclimation; Induction; Adaptation; Decay.