Booth, J., Marino, F., & Ward, J. J. (1997). Improved running performance in hot humid conditions following whole body precooling. Medicine and Science in Sports and Exercise, 29, 943-949.

Ss (N = 8) were precooled by cold water immersion prior to one of two trials of attempting to run the greatest distance possible in 30 minutes while self-controlling treadmill speed in 32 degrees Celsius with 60% humidity.

Precooling significantly increased the distance run (304 m) and decreased pre-exercise rectal and mean skin temperatures. During the exercise, body temperature remained lower than in the non-cooled trial. There was no difference in VO2 between the two conditions.

Implication. Water immersion precooling increases exercise endurance performance in hot, humid conditions while enhancing heat storage and reducing thermoregulatory strain.

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