SHORT-TERM HEAT ACCLIMATION LASTS ONE WEEK
Garrett, A. T., Goossens, N. G., Rehrer, N. J., Patterson, M. J., & Cotter, J. D. (2003). The induction and decay of short-term heat acclimation. Medicine and Science in Sports and Exercise, 35(5), Supplement abstract 158.
This study investigated adaptation to and decay from short-term heat acclimation. Moderately trained males (N = 10) underwent heat acclimation for 90-min on five consecutive days (39.5oC) under controlled hyperthermia. Ss completed a standardized heat stress test (90-min cycling at 40% peak power, followed by an incremental test) one week before acclimation and then on the second and eighth day following acclimation in 35oC. Seven Ss completed further tests at two and three weeks after acclimation.
Rectal temperature was not affected by acclimation but at the end of exercise it was 0.3oC lower. The decrease remained for one week but not two. A similar pattern was noted for heart rate. Performance after acclimation remained higher after one week but not two.
Implication. Short-term heat acclimation produced increased heat loss in exercise but not at rest. The adaptation lasted one week but had dissipated by the second week after acclimation.
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