Heat stroke in endurance exercise.

Six athletes were examined immediately after collapsing from heat stroke during exercise, and then followed for several weeks. At the time of collapse most of the patients were sweating profusely, their rectal temperatures being more than 42 degrees C. All recovered within a few hours. The renal function was not disturbed more than expected during heavy exercise, serum levels of liver enzymes were, however, increased for several weeks. Electrolyte homeostasis was undisturbed but for a transient hypercalcemia that can not be fully explained. The marked increments in plasma levels of catecholamines, vasopressin and renin were as expected after heavy exercise. We conclude that as heat stroke presents as a continuum of clinical pictures, biochemical evidence of liver cell injury is a sensitive and important parameter for the diagnosis.