Morrison, J. P., Hopkins, W. G., & Sleivert, G. G. (1999). Effect of heat acclimation on endurance performance at normal temperatures in trained cyclists. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 1389.

Acclimation to heat produces physiological adaptations similar to those of endurance training. This study assessed whether those adaptations enhance endurance performance in normal temperatures. Competitive male cyclists (N = 9) completed seven days of control acclimatization (90 minutes of cyclosimulator training, 20 degrees Celsius, 50% humidity) and seven days of heat acclimatization (exercise of similar perceived intensity, 37 degrees Celsius, 50% humidity). Two weeks separated the acclimation periods. On the first and last days of each acclimation, a fixed workload was cycled and physiological responses measured.

Heat acclimation improved performance marginally. There were only weak relationships between measures of acclimation, possibly because prior training allowed little room for heat adaptation. In some Ss, heat acclimation actually slowed performance.

Implication. Heat acclimatization does not improve endurance performance at normal temperatures.

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