Heat illness is a spectrum of disorders due to environmental exposure to heat. It includes minor conditions such as heat cramps, heat syncope, and heat exhaustion as well as the more severe condition known as heat stroke. Heat illness can relate to many of the organs and systems including: brain, heart, kidneys, liver, etc.
Heat stroke - Defined by a body temperature of greater than 40 °C (104 °F) due to environmental heat exposure with lack of thermoregulation. Symptoms include dry skin, rapid, strong pulse and dizziness.
Heat exhaustion - Can be a precursor of heatstroke; the symptoms include heavy sweating, rapid breathing and a fast, weak pulse.
Heat syncope - Fainting or dizziness as a result of overheating.
Mild disease can be treated with fluids by mouth. In more significant disease spraying with mist and using a fan is useful. For those with severe disease putting them in lukewarm water is recommended if possible with transport to a hospital.
A 2016 U.S. government report said that climate change could result in "tens of thousands of additional premature deaths per year across the United States by the end of this century." Indeed, between 2014 and 2017, heat exposure deaths tripled in Arizona (76 deaths in 2014; 235 deaths in 2017) and increased fivefold in Nevada (29 deaths in 2014; 139 deaths in 2017).
Between 1999 and 2003, the US had a total of 3442 deaths from heat illness. Those who work outdoors are at particular risk for heat illness, though those who work in poorly-cooled spaces indoors are also at risk. Between 1992 and 2006, 423 workers died from heat illness in the US.
Heat stroke is relatively common in sports. About 2 percent of sports-related deaths that occurred in the United States between 1980 and 2006 were caused by exertional heat stroke. Football in the United States has the highest rates.
Heat illness used to be blamed on a tropical fever named calenture.
^ abLipman, GS; Eifling, KP; Ellis, MA; Gaudio, FG; Otten, EM; Grissom, CK; Wilderness Medical, Society (December 2013). "Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness". Wilderness & environmental medicine. 24 (4): 351–61. doi:10.1016/j.wem.2013.07.004. PMID24140191.