LaBudde, B. D., Papadopoulos, C., Doyle, J. A., Ingalls, C. P., & Martin, D. E. (2004). The effect of heat stress on metabolic alterations during a 10-km performance run. Medicine and Science in Sports and Exercise, 36(5), Supplement abstract 571.

Male distance runners (N = 9) completed two 10-km treadmill time-trials in neutral and hot conditions.

Two Ss could not complete the run in the hot condition. Running performance took longer in the hot than neutral condition. Running speed slowed for the second half of the hot trial. A high rectal temperature preceded reduction in performance. No differences between trials were observed for hypoxanthine, xanthine, or urate. Blood lactate and plasma glucose were higher during the latter stage of the neutral condition trial.

Implication. The lower lactate and unaltered plasma levels of hypoxanthine, xanthine, and urate suggest that reduced performance in the heat was not related to metabolic processes. Performance slowing appeared to be related to achieving a high rectal temperature reading.

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