Heat-Related Deaths in the United States, 2004–2018

Deaths from natural heat exposure are largely preventable, yet they remain a public health problem. CDC analyzed national death records from 2004 to 2018 to see who died, where, and what other conditions were involved.

The toll

Over the 15 years, 10,527 deaths were linked to heat — an average of 702 a year. For 415 of those a year, heat was the underlying cause; for 287, it was a contributing cause. About 90% happened between May and September, and the death rate was highest in 2006, 2011 and 2018.

Arizona, California and Texas, home to about 23% of the U.S. population, accounted for 37% of heat-related deaths.

Who died

• Men — 70% of deaths, and more than women in every age group except infants.
• Older adults — people 65 and older accounted for 39% of deaths and had the highest rate, 0.7 per 100,000. Of the rest, 35% were 45–64, 19% were 15–44 and 7% were under 15.
• American Indian and Alaska Native people — the highest rate of any group, 0.6 per 100,000. Non-Hispanic white people had the most deaths (6,602), and non-Hispanic Black people the second-most deaths (1,965) and second-highest rate (0.3).
• By place, rates were highest in both the most rural (“noncore”) counties and large central cities, each 0.3 per 100,000.

Heat as a contributing cause

For 41% of heat-related deaths, heat contributed to a death with another underlying cause, most often:

• cardiovascular disease (49%) — including ischemic heart disease (34%) and high blood pressure (10%); and
• external causes (36%) — including alcohol poisoning and drug overdoses (18%).

Why some people are more at risk

• Older people may regulate body temperature less well and are more often socially isolated.
• Young and healthy people are at risk too when they exert themselves outdoors in heat.
• Men may differ in how their bodies handle heat and more often work in risky outdoor jobs such as farming and construction.
• Social vulnerability — less green space, more heat-absorbing surfaces, lower incomes, no air conditioning — tracks with higher heat risk and may help explain differences between racial and ethnic groups.
• Chronic disease and medicines: heat can worsen high blood pressure and heart disease, and drugs for them, such as beta-blockers, diuretics and calcium-channel blockers, can blunt the body’s response to heat.
• Alcohol and drugs such as methamphetamine and cocaine raise the risk; cocaine overdose deaths have been found to rise during extreme heat.
• Some mental health conditions can reduce awareness of dangerous heat.

Prevention

Effective steps include reaching out to vulnerable communities about the symptoms of heat illness and how to stay cool and hydrated — especially young athletes and older or isolated people — monitoring weather and emergency department data to time warnings, heat response plans, education, and cooling centers. CDC recommends that federal, state, local and tribal authorities open cooling centers or public air-conditioned places during hot weather; during the COVID-19 pandemic it also issued guidance on running them safely. The authors call for coordination across the health care system to prevent heat deaths.

Limitations

• Heat contributes to many deaths that death certificates may not record as heat-related.
• Deaths are counted by where people lived, not where they were exposed.
• Death records often lack detail on the circumstances.

Sources

Based on Vaidyanathan A, Malilay J, Schramm P, Saha S, "Heat-Related Deaths — United States, 2004–2018," Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; a work of the United States government in the public domain.