Beat the Heat: Strategies for Preventing Heat-Related Illness and Death

A 19-year-old hiker died of apparent heatstroke after she was found lying unconscious beside a trail in a remote area of southern California. The outdoor temperature was at least 37.8°C (100°F).

A 61-year-old woman was found dead in a sauna after she had been drinking. Her blood alcohol level was 0.21%. The sauna room temperature was 32.2°C (90°F), and the sauna had no timer.

A 48-year-old man collapsed in his home and was pronounced dead on arrival at the hospital. He weighed more than 300 lb and had a history of hypertension. The outdoor temperature was about 35°C (95°F), and his home was not air-conditioned.

These three cases are examples of heat-related mortality. From 1999 through 2003, a total of 3442 deaths in the United States resulted from exposure to extreme heat (the annual mean was 688).1 Heat-related illnesses include heatstroke, heat exhaustion, heat syncope, and heat cramps.

Heatstroke is characterized by rapid onset and progression of the core body temperature to 39.4°C (103°F) or higher and lethargy, disorientation, delirium, and coma.2 It is often fatal. Heat exhaustion is marked by dizziness, weakness, or fatigue, often following several days of sustained exposure to hot temperatures. It results from dehydration and electrolyte imbalance; affected patients may require hospitalization.

While all persons are at increased risk if they are exposed to excessive heat, elderly persons, young children, and persons with chronic medical conditions are particularly susceptible to heat-related illness and mortality. The association between cardiovascular disease and heat-related death is well established.3 Additional risk factors are shown in Table 1.

The CDC recommends providing information about heat-related illness to susceptible populations. This includes educating parents about the increased risk among children younger than 5 years. During heat waves, young children, older adults, and persons with chronic medical disorders should be checked frequently by relatives, neighbors, and caretakers to evaluate their heat exposure, recognize symptoms of heat-related illness, and take appropriate preventive action. Examples of preventive strategies are shown in Table 2


1. CDC. Heat-related deaths—United States, 1999–2003. MMWR. 2006;55(29):796-798.

2. Lugo-Amador NM, Rothenhaus T, Moyer P. Heat-related illness. Emerg Med Clin North Am. 2004;22:315-327.

3. Wainwright SH, Buchanan SD, Mainzer HM, et al. Cardiovascular mortality—the hidden peril of heat waves. Prehospital Disaster Med. 2000;15:79.