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Optimising the acquisition and retention of heat acclimation.
Int J Sports Med. 2011 Nov; 32(11):822-8.IJ

Abstract

Heat acclimation (HA) often starts in a moderately hot environment to prevent thermal overload and stops immediately prior to athletic activities. The aims of this study were (1) to establish whether acclimation to a moderately hot climate is sufficient to provide full acclimation for extreme heat and (2) to investigate the physiological responses to heat stress during the HA decay period. 15 male subjects exercised for 9 consecutive days at 26° C Wet Bulb Globe Temperature (WBGT) and 3 days at 32° C WBGT on a cycle ergometer for up to 2 h per day and repeated the exercise 3, 7 and 18 days later in 26° C WBGT. Rectal temperature (T (re)) and heart rate (HR) were measured during 60 min of steady state exercise (∼45% of maximum oxygen uptake). During days 1-9, end-exercise T (re) was reduced from 38.7±0.1 to a plateau of 38.2±0.1° C (p<0.05), HR was reduced from 156±10 to 131±11 bpm (p<0.05). No changes in HR and T (re) occurred during the 3 days in the very hot environment. However, T (re) during rest and exercise were significantly lower by 0.4-0.5° C after HA compared with day 9, suggesting that heat acclimation did not decay but resulted in further favourable adaptations.

Authors+Show Affiliations

TNO Defence, Security and Safety, Department of Human Performance, Soesterberg, The Netherlands. hein.daanen@tno.nlNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22052034

Citation

Daanen, H A M., et al. "Optimising the Acquisition and Retention of Heat Acclimation." International Journal of Sports Medicine, vol. 32, no. 11, 2011, pp. 822-8.
Daanen HA, Jonkman AG, Layden JD, et al. Optimising the acquisition and retention of heat acclimation. Int J Sports Med. 2011;32(11):822-8.
Daanen, H. A., Jonkman, A. G., Layden, J. D., Linnane, D. M., & Weller, A. S. (2011). Optimising the acquisition and retention of heat acclimation. International Journal of Sports Medicine, 32(11), 822-8. https://doi.org/10.1055/s-0031-1279767
Daanen HA, et al. Optimising the Acquisition and Retention of Heat Acclimation. Int J Sports Med. 2011;32(11):822-8. PubMed PMID: 22052034.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optimising the acquisition and retention of heat acclimation. AU - Daanen,H A M, AU - Jonkman,A G, AU - Layden,J D, AU - Linnane,D M, AU - Weller,A S, Y1 - 2011/11/03/ PY - 2011/11/5/entrez PY - 2011/11/5/pubmed PY - 2012/3/1/medline SP - 822 EP - 8 JF - International journal of sports medicine JO - Int J Sports Med VL - 32 IS - 11 N2 - Heat acclimation (HA) often starts in a moderately hot environment to prevent thermal overload and stops immediately prior to athletic activities. The aims of this study were (1) to establish whether acclimation to a moderately hot climate is sufficient to provide full acclimation for extreme heat and (2) to investigate the physiological responses to heat stress during the HA decay period. 15 male subjects exercised for 9 consecutive days at 26° C Wet Bulb Globe Temperature (WBGT) and 3 days at 32° C WBGT on a cycle ergometer for up to 2 h per day and repeated the exercise 3, 7 and 18 days later in 26° C WBGT. Rectal temperature (T (re)) and heart rate (HR) were measured during 60 min of steady state exercise (∼45% of maximum oxygen uptake). During days 1-9, end-exercise T (re) was reduced from 38.7±0.1 to a plateau of 38.2±0.1° C (p<0.05), HR was reduced from 156±10 to 131±11 bpm (p<0.05). No changes in HR and T (re) occurred during the 3 days in the very hot environment. However, T (re) during rest and exercise were significantly lower by 0.4-0.5° C after HA compared with day 9, suggesting that heat acclimation did not decay but resulted in further favourable adaptations. SN - 1439-3964 UR - https://www.unboundmedicine.com/medline/citation/22052034/Optimising_the_acquisition_and_retention_of_heat_acclimation_ L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-0031-1279767 DB - PRIME DP - Unbound Medicine ER -