64 Heat Exhaustion Statistics on Emergency Care, Work and Sports

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Heat exhaustion is measured through several different systems, so no single number captures its full scale. The figures below distinguish heat exhaustion from broader heat illness, identify the population and period measured, and separate emergency-care, occupational, military, sports and claims data.

Key Heat Exhaustion Statistics

The most useful headline figures span emergency care, exposure settings and broader heat-related illness surveillance:

  • 326,497 acute heat-illness emergency-department cases were estimated in the United States during May–September 2006–2010.
  • Heat exhaustion represented 74.7% of U.S. acute heat-illness ED cases during 2006–2010.
  • 88.2% of estimated U.S. acute heat-illness ED cases were treated and released during 2006–2010.
  • 11.8% of estimated U.S. acute heat-illness ED cases were admitted to hospital during 2006–2010.
  • 94% of U.S. acute heat-illness visits occurred from May 1 through September 30 during 2006–2010.
  • 2,263 heat-exhaustion cases occurred among U.S. active-component service members in 2023.
  • The military heat-exhaustion incidence rate rose 8.0% from 2022 to 2023 among U.S. active-component service members.
  • Female U.S. service members had a 24% higher heat-exhaustion rate than male service members in 2023.
  • Construction recorded 620 nonfatal days-away-from-work heat injuries in the United States during 2021–2022.
  • Heat exhaustion or prostration accounted for 67.7% of construction’s nonfatal heat injuries during 2021–2022.
  • NCAA exertional heat-illness incidence was 0.47 events per 10,000 athlete-exposures from 2009–2010 through 2014–2015.
  • Football accounted for 75% of reported NCAA exertional heat-illness events from 2009–2010 through 2014–2015.
  • Preseason NCAA practice had 1.16 exertional heat illnesses per 10,000 athlete-exposures during 2009–2010 through 2014–2015.
  • The highest monthly U.S. HRI incidence was 130.97 per 100,000 person-years in July 2019 in a 2017–2022 electronic-health-record cohort.
  • CDC recorded 303 HRI ED visits per 100,000 ED visits in July–August 2023 across the United States.
  • Taiwan identified 101,614 HRI patients in nationwide health-insurance data from 2000–2018.

Contents

U.S. Emergency-Department Heat Exhaustion Data

A nationally representative U.S. emergency-department study estimated 326,497 acute heat-illness cases during May–September 2006–2010, with a 95% confidence interval of 308,372–344,658. The study average was 65,299 visits per summer year, or 21.5 visits per 100,000 population per year; these measures cover all acute heat illness, not heat exhaustion alone. CDC Stacks, Summertime Acute Heat Illness in U.S. Emergency Departments from 2006 through 2010

U.S. ED measure Result Population and period
Heat exhaustion share 74.7% Acute heat-illness cases, 2006–2010
Heat stroke share 5.4% Acute heat-illness cases, 2006–2010
Treat-and-release cases 287,875 (88.2%) Acute heat illness, 2006–2010
Hospital admissions 38,392 (11.8%) Acute heat illness, 2006–2010
Deaths in ED 230 (0.07%) Acute heat illness, 2006–2010

Heat illness was the first-listed diagnosis in 68% of these ED cases, while the remaining cases had heat illness in a secondary diagnosis position. Ninety-four percent of visits occurred between May 1 and September 30, showing strong seasonal concentration in this dataset rather than a universal climate threshold.

Rates also varied by age and outcome. Treat-and-release visits were highest among younger adults at 26.2 per 100,000 population per year, while hospitalization was highest among older adults at 6.7 per 100,000 and death-in-ED was highest among older adults at 0.03 per 100,000 per year.

The heat-stroke subgroup illustrates why severity categories matter: its ED case-fatality rate was 99.4 deaths per 10,000 heat-stroke visits, with a 95% confidence interval of 78.7–120.1, and heat stroke was diagnosed in 77.0% of ED deaths. These are heat-stroke measures, not heat-exhaustion mortality measures.

Military surveillance provides a defined population with person-year denominators, but it should not be treated as general-population prevalence. Among U.S. active-component Army, Navy, Marine Corps, Air Force, Space Force and Coast Guard service members, 2,263 heat-exhaustion cases occurred in 2023, at 172.7 cases per 100,000 person-years. Health.mil, Heat Exhaustion and Heat Stroke Among Active Component Members of the U.S. Armed Forces, 2019–2023

  • From 2019 to 2023, the crude annual heat-exhaustion incidence rate increased 4.6%.
  • From 2022 to 2023, the crude annual rate increased 8.0%.
  • Female service members had a rate 24% higher than male service members in 2023.
  • Recruits’ rate was 12.5 times the rate of other enlisted service members and 13.5 times the officer rate in 2023.

Across 2019–2023, 12,488 heat illnesses were diagnosed at more than 250 military installations and locations worldwide. Of those broader heat-illness cases, 5.8% occurred outside the United States, while 21 locations with at least 100 cases accounted for 77.5% of all active-component cases.

The 2022 surveillance report recorded 1,912 heat-exhaustion cases at 147.7 per 100,000 person-years. Service members younger than 20 recorded 503 cases at 622.0 per 100,000 person-years, compared with 834 cases at 202.6 per 100,000 among those aged 20–24. Health.mil, MSMR April 2023: Heat Illness, Active Component, U.S. Armed Forces, 2022

Workplace Heat Exhaustion Statistics

Occupational data measure recorded nonfatal injuries, not all community cases of heat exhaustion. In U.S. private construction, days-away-from-work heat injuries fell from 1,500 in 2011–2012 to 620 in 2021–2022, a reported 57.2% decline; the chart counts are rounded to the nearest 0.1K.

Across all private industries, the comparable count fell from 6.7K to 4.9K, a 26.9% decline. CPWR Data Bulletin — Heat Injuries and Illnesses

Occupational measure 2011–2012 2021–2022
Construction nonfatal heat injuries 1,500 620
Construction rate per 10,000 FTEs 1.2 0.4
All-industry count 6.7K 4.9K
All-industry rate per 10,000 FTEs 0.3 0.2

In construction during 2021–2022, heat exhaustion or prostration accounted for 420 injuries, or 67.7% of the total. Another 130 injuries were coded as effects of heat and light not elsewhere classified, a category that includes heat edema and dehydration, while 60 were coded as heat stroke.

OSHA severe-injury reports from 2015–2023 provide a different denominator: heat exhaustion represented 19.0% of severe construction heat injuries by nature code. Among those severe injuries, 95.4% were coded as exposure to environmental heat and 4.2% as falls; heat may contribute to falls without being the primary event code.

College Sports and Recreation Heat Illness

NCAA athletic-trainer surveillance reported 232 exertional heat-illness events across 2,048 team-seasons from 2009–2010 through 2014–2015, using a voluntary sample of 166 institutions and sanctioned practice or competition only. Overall incidence was 0.47 events per 10,000 athlete-exposures, with a 95% confidence interval of 0.41–0.53. PubMed, Epidemiology of Exertional Heat Illnesses in NCAA Athletes

Football accounted for 75% of events and had the highest sport-specific rate at 1.55 per 10,000 athlete-exposures, with a 95% confidence interval of 1.32–1.78. Preseason practice had a rate of 1.16 per 10,000 exposures versus 0.23 in other periods, producing a preseason-to-other-period rate ratio of 4.96, with a 95% confidence interval of 3.79–6.50.

Among reported NCAA exertional heat illnesses, heat cramps represented 39%, heat exhaustion 27% and dehydration 29%; percentages may not sum to 100% because of other diagnoses or rounding. Eight percent of affected athletes required emergency transport, representing 19 athletes.

A broader U.S. sports-and-recreation ED estimate found 5,946 heat-illness treatments per year during 2001–2009, or 2.0 visits per 100,000 population per year. That estimate includes recreational activity and all sports-related heat illness, not heat exhaustion alone. PubMed, Nonfatal sports and recreation heat illness treated in hospital emergency departments

A U.S. electronic-health-record cohort of 33,603,572 people followed from 2017–2022 identified 10,652 people with an HRI diagnosis. The median age among HRI patients was 49 years, and 62.3% were male. PubMed, Secular trends in heat related illness and excess sun exposure rates

The highest overall monthly HRI incidence was 130.97 per 100,000 person-years in July 2019, with a 95% confidence interval of 119.93–142.75. The highest regional incidence was 186.04 per 100,000 in the U.S. South during 2020, with a 95% confidence interval of 117.93–279.15.

Temperature and HRI incidence were strongly correlated in the West, where the Pearson correlation was 0.854, and in the Southwest, where it was 0.832. These are associations and do not establish that temperature alone caused each illness.

CDC syndromic surveillance found 303 HRI ED visits per 100,000 ED visits in July–August 2023, compared with 97 in May, June and September. The rate ratio was 3.07, with a 95% confidence interval of 2.85–3.30; these are rates among ED visits, not population incidence. CDC MMWR, Heat-Related Emergency Department Visits — United States, May–September 2023

For the 2018–2022 warm-season comparison period, the July–August rate was 208 per 100,000 ED visits and the rate ratio was 1.84, with a 95% confidence interval of 1.72–1.97. CDC’s 2023 analysis retained data from as many as 823 ED facilities, with a median of 111 participating facilities across the reporting range, so coverage varied over time.

Taiwan’s nationwide health-insurance study identified 101,614 HRI patients from 2000–2018. Males comprised 56.2% of patients, the mean age was 48.2 years, and adults aged 20–44 represented 44.8% of the cohort. PubMed, Epidemiological characteristics of heat-related illness: a nationwide study in Taiwan

Hospital treatment occurred for 51.6% of male versus 25.3% of female HRI patients. Among Taiwan’s heat-stroke subgroup, 7-day mortality was 0.5%, 1-month mortality was 0.7% and 3-month mortality was 1.0%; these cumulative follow-up measures concern heat stroke, not heat exhaustion.

Threshold data also show why a single heat-index cutoff should not be treated as a universal boundary. At least 25% of heat-related illnesses among Washington agriculture and forestry workers occurred at a Heat Index below 90°F (32.2°C), while 14% of moderate-to-severe heat-related illnesses at a U.S. military training installation occurred below the same threshold. CDC MMWR, Evaluation of Occupational Exposure Limits for Heat Stress in Outdoor Workers — United States, 2011–2016

The datasets above are not directly additive: ED records, occupational reports, military surveillance, NCAA observations, claims and electronic-health records capture different populations, definitions, care-seeking patterns and reporting processes. Broader heat-illness and HRI figures are included for context and are labeled separately from heat-exhaustion-specific measures.

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