Heat-related deaths--United States, 1999-2003.

Heat-related illnesses (e.g., heat cramps, heat exhaustion, heat syncope, or heatstroke) can occur when high ambient temperatures overcome the body's natural ability to dissipate heat. Older adults, young children, and persons with chronic medical conditions are particularly susceptible to these illnesses and are at high risk for heat-related mortality. Previous analyses of the risk factors associated with heat-related deaths have been based on the underlying cause entered on the death certificate and have not included decedents for whom hyperthermia was listed as a contributing factor but not the underlying cause of death. This report describes an analysis in which number of heat-related deaths were counted, including deaths in which hyperthermia was listed as a contributing factor on the death certificate. The analysis revealed that including these deaths increased the number of heat-related deaths by 54% and suggested that the number of heat-related deaths is underestimated.