Top 5 Takeaways

  1. Significant Increase in Heat-Related Illnesses: Emergency department (ED) visits for heat-related illnesses in the U.S. spiked during May–September 2023, especially among males and adults aged 18–64.
  2. Impact of Climate Change: The continuation of this trend is expected as climate change leads to more frequent, longer, and more intense heatwaves, highlighting the urgency for public health preparedness.
  3. Demographic and Regional Variability: There were notable differences in heat-related ED visit rates by age, sex, and region, with regions like Texas and Oklahoma experiencing the highest rates.
  4. Public Health Alerts and Actions: The CDC utilized the Epidemic Information Exchange to issue alerts and drive public health actions in response to rising heat-related health issues.
  5. Strategic Public Health Recommendations: Enhanced monitoring and timely public health interventions are crucial to mitigate the impacts of extreme heat, especially on vulnerable populations.

Corresponding Author and Citation

Corresponding Author

Ambarish Vaidyanathan,

Suggested Citation

Vaidyanathan A, Gates A, Brown C, Prezzato E, Bernstein A. Heat-Related Emergency Department Visits — United States, May–September 2023. MMWR Morb Mortal Wkly Rep 2024;73:324–329. DOI:


This report outlines the alarming increase in ED visits for heat-related illnesses across the U.S. during the warm-season months of 2023. The findings underscore the escalating impact of climate change on public health and the critical need for effective heat wave preparedness and response strategies.


The CDC analyzed data from the National Syndromic Surveillance Program (NSSP) to compare the rate of heat-related illness ED visits from May to September 2023 with previous years, focusing on demographic and regional variations.


The discussion highlights the increased frequency and severity of heatwaves as a significant public health issue, emphasizing the need for targeted communication and interventions, particularly for high-risk populations and regions.


Given the trends observed in 2023 and the ongoing challenges posed by global warming, public health strategies must prioritize enhanced surveillance, risk communication, and community-specific interventions to prevent heat-related illnesses.

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