In racing Thoroughbreds, even after exercise is complete, core temperatures can continue to increase, particularly where mechanisms of heat dissipation are impaired by heat and humidity. The heat accumulated may exceed a critical thermal maximum, which may trigger a complex pathophysiological cascade. Often, central nervous system signs may appear, progressing from irritability to unmanageable horses and, ultimately, convulsions, coma, and death.
Courtesy of Dr. Meg Brownlow.