Table 1.

Heat-related illnesses (modified from Mangus and Canares, 2019).

Mild
Miliaria	Heat rash, prickly heat
Heat edema	Distal extremities; 2° vasodilation and vascular pooling
Heat cramps	Exercise-induced cramping: predisposed by dehydration, lack of conditioning and/or of acclimatization
Heat syncope	Normal core temperature; 2° vasodilation and vascular pooling; must rule out heat exhaustion
Heat stress	Normal core temperature but experiencing discomfort in warm environment
Moderate
Heat exhaustion	Increase in core temperature (37 °C–40 °C) along with symptoms of thirst, headache, weakness, syncope, vomiting, dizziness. Often associated with dehydration and heavy sweating. Tachycardia and hypotension often present, but no central nervous system signs or symptoms (except mild headache or slight confusion). Without prompt treatment can rapidly progress to heat stroke
Severe
Heat stroke	Life-threatening condition with core temperature >40 °C accompanied by central nervous system dysfunction (agitation, confusion, delirium, or coma) in setting of warm environment and/or vigorous exercise
	Rapid progression to multisystem organ failure with a high mortality (Epstein and Roberts, 2011)