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Hypothermia Prevention

From 1976 through 1985, 7450 deaths were caused by exposure to cold* in the United States (Figure 1). Of health effects associated with cold exposure, hypothermia--defined as a core body temperature of less than or equal to35 C (less than or equal to95 F)--is the most commonly fatal syndrome. Persons greater than or equal to60 years of age are particularly susceptible to hypothermia and account for more than half of all deaths (1). Younger persons subjected to overwhelming cold stress are also vulnerable (2). Although deaths attributable to hypothermia occur infrequently in children, infants less than 1 year of age are at relatively high risk. Rates of death from hypothermia are generally higher in males than in females, but these differences are less substantial in children and the elderly (3).

Persons with hypothyroidism are at increased risk for hypothermia (4). In addition, a variety of drugs, principally sedative-hypnotics, may predispose users to hypothermia; ethanol and neuroleptic medications particularly increase susceptibility to cold (2).

As the body temperature of a cold-exposed person decreases, impaired consciousness, confusion, or disorientation may occur. Because mental status is altered, a mildly hypothermic person may fail to take appropriate corrective measures to lessen exposure. In response to the decline in core temperature, vasoconstriction (causing pallor) and shivering occur. However, shivering decreases markedly in severe hypo- thermia because thermoregulation becomes impaired. Severely hypothermic persons lose consciousness and develop shallow respirations. Ventricular fibrillation and death may follow (2). Reported by: Health Studies Br, Div of Environmental Hazards and Health Effects, Center for Environmental Health and Injury Control, CDC.

Editorial Note

Editorial Note: This preliminary study of mortality data suggests a trend toward increased incidence of hypothermia. Although age-adjusted rates are required to properly evaluate the hypothesis that mortality due to effects of cold is increasing, the crude numbers of deaths (Figure 1) strongly suggest such a trend.

Hypothermia prevention programs should focus on persons particularly susceptible to hypothermia and those likely to be subjected to unusual cold stress. Persons caring for the elderly should be alerted to hypothermia's symptoms and signs, and elderly persons living alone should be visited frequently. Since adequate caloric intake is important in preventing hypothermia, programs designed to improve nutrition in the elderly may also be helpful. Programs that ensure home heating for the elderly may also help prevent hypothermia.

Younger persons likely to be subjected to cold stress (e.g., skiers and hikers) should be educated concerning the need for adequate clothing and the importance of abstaining from alcohol use during prolonged cold exposure. Shelter should be offered to homeless persons who would otherwise sleep outdoors on cold winter nights.

Persons using medications (particularly neuroleptic medications) that are likely to increase susceptibility to the cold should be advised by their physicians regarding their increased vulnerability to cold stress.


  1. Kilbourne EM. Illness due to thermal extremes. In: Last JM, ed. Maxcy-Rosenau public health and preventive medicine. 12th ed. Norwalk, Connecticut: Appleton-Century-Crofts, 1986: 711-4. 2.Collins KJ. Hypothermia: the facts. New York: Oxford University Press, 1983. 3.CDC. Hypothermia-associated deaths--United States, 1968-1980. MMWR 1985;34:753-4. 4.Forester CF. Coma in myxedema: report of a case and review of the world literature. Arch Intern Med 1963;111:734-43. *Deaths attributed to excessive cold (ICD code E901) were analyzed using mortality data tapes for 1976-1985 from the National Center for Health Statistics.

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