Jogger's heat stroke.

Two patients developed heat stroke following jogging. Transient disturbance of cerebral function was the most dramatic clinical feature. Although haemorrhagic complications were not seen, marked changes in the haemostatic system occurred with both thrombocytopenia and a reduction of clotting factors synthesised by the liver. No evidence of disseminated intravascular coagulation was found. Heat stroke must now be added to the list of jogging hazards.