Colder Weather Linked to 40,000 Heart-Related Deaths Yearly in the United States, Study Finds
Mount Sinai-led research shows significantly more cardiac mortality occurs during cooler temperatures than in excessive heat
Mount Sinai-led research shows significantly more cardiac mortality occurs during cooler temperatures than in excessive heat
Study Title: “Cardiovascular disease mortality attributable to monthly non-optimal temperature in the United States: a county-level analysis”
Conference: American College of Cardiology Scientific Sessions - Young Investigators Award Competition Finalist: “Outcomes Research” Presentation (Monday, March 30, 9:30 am CDT in New Orleans)
Journal: Journal of the American Journal of Preventative Cardiology (simultaneous publication)
Bottom line of the study: Colder temperatures are responsible for significantly more cardiovascular deaths from heart attacks, strokes, and coronary artery disease than milder months/warm temperatures in the United States. Heat consistently gets more attention as a cause for concern for heart patients; however, this study shows colder weather is the larger and more consistent risk.
Why this study is important: Most public health messaging focuses on heat waves, but this study’s findings show that colder temperatures are associated with a substantially higher number of heart-related deaths each year. This highlights a major gap in awareness and prevention.
Why this study is unique: This research is the most comprehensive analysis of temperature-related trends to date across the United States. Previous studies have linked extreme temperatures with increased risk of cardiovascular death, but most have focused on other countries or smaller sections of the United States.
How the study was conducted: Researchers analyzed more than 14 million cardiovascular deaths of people over 25 years old across 819 counties in the United States (80 percent of the country’s population) between 2000 and 2020. They linked mortality data with local temperature data and used statistical models to estimate how deviations from optimal temperatures were associated with cardiovascular death risk. They then quantified how many deaths were attributable to cold versus heat exposure.
Results: The researchers determined that the optimal temperature for heart health—the temperature at which the least mortality occurred—was 74 degrees Fahrenheit. Mortality risk rose asymmetrically when moving away from that point, with temperatures under 74 degrees Fahrenheit accounting for approximately 40,000 cardiovascular deaths each year of the study period (6.3 percent), while temperatures over 74 degrees accounted for about 2,000 cardiovascular deaths each year (.33 percent). In total, colder weather was linked to roughly 800,000 deaths over two decades, compared to 40,000 deaths due to warm weather.
Put differently, one in 16 cardiovascular deaths were linked to colder weather compared to one in 300 linked to heat.
Further details and explanation of the analysis: Approximately 80 percent of the observations occurred at temperatures below 74 degrees. The researchers used statistical techniques to adjust for this, but even with the adjustments, and determined that heart mortality was more common on days below 74.
What this means for clinicians: Clinicians should recognize cold exposure as a meaningful cardiovascular risk factor. Risk increases during colder months, particularly among older adults and patients with underlying cardiovascular disease, and should be incorporated into seasonal risk assessment and preventive counseling.
What this means for heart patients: Cold weather can place additional strain on the heart. Patients, especially those with cardiovascular disease, should stay warm, avoid sudden exertion in the cold such as snow shoveling, and remain consistent with their medications. In some patients, medication adjustments may be needed during periods of extreme cold temperature.
Quotes from Lead Author/Presenter: Pedro Rafael Vieira De Olivera Salerno, MD, Internal Medicine Resident in the Icahn School of Medicine of Mount Sinai program at NYC Health + Hospitals/Elmhurst.
“This may be surprising to many, but most temperature-related cardiovascular deaths are associated with cold, not heat. While heat waves are a major focus for health issues, colder temperatures are associated with far more heart-related deaths over time,” says Dr. Salerno. “As clinicians, we see seasonal patterns in cardiovascular events, but this helps quantify how much cold exposure contributes at the population level. This isn’t just about extreme weather. Even routine cold exposure, especially in vulnerable patients, can increase cardiovascular risk.”
Institutions involved in the study: The study was led by researchers at the Icahn School of Medicine of Mount Sinai and NYC Health + Hospitals/Elmhurst and done in collaboration with Houston Methodist and Case Western Reserve University.
About the Icahn School of Medicine at Mount Sinai
The Icahn School of Medicine at Mount Sinai is internationally renowned for its outstanding research, educational, and clinical care programs. It is the sole academic partner for the seven member hospitals* of the Mount Sinai Health System, one of the largest academic health systems in the United States, providing care to New York City’s large and diverse patient population.
The Icahn School of Medicine at Mount Sinai offers highly competitive MD, PhD, MD-PhD, and master’s degree programs, with enrollment of more than 1,200 students. It has the largest graduate medical education program in the country, with more than 2,700 clinical residents and fellows training throughout the Health System. Its Graduate School of Biomedical Sciences offers 13 degree-granting programs, conducts innovative basic and translational research, and trains more than 560 postdoctoral research fellows.
Ranked 11th nationwide in National Institutes of Health (NIH) funding, the Icahn School of Medicine at Mount Sinai is among the 99th percentile in research dollars per investigator according to the Association of American Medical Colleges. More than 4,500 scientists, educators, and clinicians work within and across dozens of academic departments and multidisciplinary institutes with an emphasis on translational research and therapeutics. Through Mount Sinai Innovation Partners (MSIP), the Health System facilitates the real-world application and commercialization of medical breakthroughs made at Mount Sinai.
-------------------------------------------------------
* Mount Sinai Health System member hospitals: The Mount Sinai Hospital; Mount Sinai Brooklyn; Mount Sinai Morningside; Mount Sinai Queens; Mount Sinai South Nassau; Mount Sinai West; and New York Eye and Ear Infirmary of Mount Sinai.
About the Mount Sinai Health System
Mount Sinai Health System is one of the largest academic medical systems in the New York metro area, with 48,000 employees working across seven hospitals, more than 400 outpatient practices, more than 600 research and clinical labs, a school of nursing, and a leading school of medicine and graduate education. Mount Sinai advances health for all people, everywhere, by taking on the most complex health care challenges of our time—discovering and applying new scientific learning and knowledge; developing safer, more effective treatments; educating the next generation of medical leaders and innovators; and supporting local communities by delivering high-quality care to all who need it.
Through the integration of its hospitals, labs, and schools, Mount Sinai offers comprehensive health care solutions from birth through geriatrics, leveraging innovative approaches such as artificial intelligence and informatics while keeping patients’ medical and emotional needs at the center of all treatment. The Health System includes approximately 9,000 primary and specialty care physicians and 10 free-standing joint-venture centers throughout the five boroughs of New York City, Westchester, Long Island, and Florida. Hospitals within the System are consistently ranked by Newsweek’s® “The World’s Best Smart Hospitals, Best in State Hospitals, World Best Hospitals and Best Specialty Hospitals” and by U.S. News & World Report's® “Best Hospitals” and “Best Children’s Hospitals.” The Mount Sinai Hospital is on the U.S. News & World Report® “Best Hospitals” Honor Roll for 2025-2026.
For more information, visit https://www.mountsinai.org or find Mount Sinai on Facebook, Instagram, LinkedIn, X, and YouTube.