After much of the United States experienced one of the coldest winters in recent memory, new research has uncovered serious dangers that are often overlooked. Colder seasons are associated with significantly higher rates of death from heart attacks, strokes, and coronary artery disease compared to milder periods. Research presented at the American College of Cardiology’s annual scientific meeting (ACC.26) also shows that hot weather increases cardiovascular mortality rates, although the increase is much smaller.
Previous studies have linked extreme temperatures to increased cardiovascular mortality, but many of those studies focused on other countries or only parts of the United States. For example, in previous studies, jack They reported that exposure to cold temperatures increases the risk of heart attack. This latest study provides the most extensive investigation to date of how temperature affects heart-related deaths in a large portion of the U.S. population.
“This is the first time we have actual numbers for most regions of the United States, and we know that the burden of excess cold-related deaths is substantial,” said Pedro Rafael Vieira de Oliveira Salerno, M.D., resident physician at NYC Health + Hospitals/Elmhurst, Icahn School of Medicine at Mount Sinai, New York, and lead author of the study.
20 years of data reveals clear patterns
The research team looked at monthly temperature data and cardiovascular mortality rates for 819 locations in the United States, covering approximately 80% of Americans over the age of 25. Examining data from 2000 to 2020, researchers found that the temperature associated with the lowest cardiovascular mortality was 23°C (about 74°F). As temperatures rose or fell above this point, mortality increased.
This relationship followed a skewed U-shaped curve. Both extreme heat and extreme cold increased the risk of death, but the effect was much stronger on the cold side. The researchers estimate that cold temperatures caused about 40,000 additional cardiovascular deaths each year during the study period (about 6.3% of all cardiovascular deaths), for a total of about 800,000 deaths over 20 years. By comparison, high temperatures are associated with approximately 2,000 additional deaths per year (approximately 0.33% of all cardiovascular disease deaths), or approximately 40,000 over the same period.
Why cold weather puts a strain on your heart
Exposure to cold triggers a chain reaction in the body, including inflammation and narrowing of blood vessels. These changes may increase the likelihood of serious cardiovascular events. Older adults and people with chronic illnesses are especially at risk.
“The prevalence of chronic diseases such as diabetes, heart failure, and chronic kidney disease is increasing in the United States, and we expect an increasing number of people to become more vulnerable to the effects of extreme temperatures,” Salerno said.
Planning for climate and public health risks
The findings suggest that communities need to pay close attention to the dangers of cold weather when preparing for climate-related health risks.
“We tend to focus on the heat-related effects of climate change, but climate change also includes extreme cold. We need not only heat-related mitigation measures, but also cold-related mitigation measures,” he said.
The results could also help hospitals and emergency services prepare for a surge in demand during the colder months.
“It is important for public health planning and for health care providers to anticipate the increase in emergency medical services and in-hospital mortality during cold weather. Our systems need to be prepared for such an influx of patients,” Salerno said.
Research limitations and next steps
The researchers note that the study used monthly temperature data rather than daily measurements, and the results were analyzed at the population level rather than individuals. Future studies will investigate how changes in temperature relate to activation of emergency medical services related to cardiovascular events.
The study was published online. American Journal of Preventive Cardiology At the time of the presentation.
Professor Salerno will present his research, “County-Level Temperature-Attributable Cardiovascular Disease Mortality in the United States,” on Monday, March 30th at 9:30 a.m./14:30 UTC on the Engage Stage of the Young Investigator Award Competition.
ACC.26 will be held in New Orleans from March 28-30, 2026, and will bring together cardiologists and cardiovascular specialists from around the world to share the latest discoveries in treatment and prevention.
