Heatstroke

Sudden illness and injury. Also called: Heat stroke, Sunstroke.

How common is Heatstroke in the US?

Emergency department (ED) visits associated with heat-related illness (HRI), from CDC's National Syndromic Surveillance Program (NSSP/ESSENCE): 119,605 (Heat-related illness ED visits, United States, calendar year 2023 (count, not a population rate); NSSP participation covered up to 823-826 EDs, which the source states is not a nationally representative sample; United States (CDC National Syndromic Surveillance Program, ESSENCE system, covering all 10 HHS regions; source notes NSSP data are not nationally representative), 2023 (January-December 2023; 92% of visits occurred May-September)). Source: MMWR. Morbidity and mortality weekly report (CDC), 2024. Label: VERIFIED.

• 119,605 Emergency department (ED) visits associated with heat-related illness (HRI), from CDC's National Syndromic Surveillance Program (NSSP/ESSENCE). Out of: Heat-related illness ED visits, United States, calendar year 2023 (count, not a population rate); NSSP participation covered up to 823-826 EDs, which the source states is not a nationally representative sample. Where: United States (CDC National Syndromic Surveillance Program, ESSENCE system, covering all 10 HHS regions; source notes NSSP data are not nationally representative). When: 2023 (January-December 2023; 92% of visits occurred May-September). ED visits only, not all heat-related illness cases (excludes those treated elsewhere, not seeking care, or who died before reaching an ED); drawn from a national syndromic surveillance sample that the source states is not nationally representative. Label: VERIFIED.

  During January 1–December 31, 2023, a total of 119,605 HRI ED visits were recorded in the ESSENCE system; 92% of these visits occurred during May–September.

  Source: Heat-Related Emergency Department Visits — United States, May–September 2023 MMWR. Morbidity and mortality weekly report (CDC), 2024. PubMed 38635484. DOI 10.15585/mmwr.mm7315a1.

Each figure measures something different. Do not compare them with each other or with other conditions.

Medical codes

• ICD-10-CM FY2026: T67.01XA Heatstroke and sunstroke, initial encounter (exact)

Research activity

As of 2026-09-24: 41 registered studies on ClinicalTrials.gov (search Heat Stroke) and 965 PubMed records, 2021 to 2025. A count of records is not how common or serious the condition is.

Population information, not medical advice. Methodology · Known limitations