Cold Weather & Heart Health: US Study Links Winter to Higher Cardiovascular Death Rates

After one of the coldest winters in recent memory for many parts of the United States, latest research presented at the American College of Cardiology’s Annual Scientific Session (ACC.26) is highlighting a significant, often overlooked risk: colder temperatures are linked to a substantial increase in deaths from heart problems. While extreme heat also poses a cardiovascular threat, the impact of cold weather is considerably more pronounced, contributing to an estimated 40,000 excess deaths annually in the U.S.

The Burden of Cold: A Two-Decade Analysis

This latest research builds on earlier findings connecting extreme temperatures to cardiovascular mortality, but offers a more comprehensive look at the issue within the United States. A study published in the Journal of the American College of Cardiology previously demonstrated a link between cold exposure and increased heart attack risk. The new analysis, led by Pedro Rafael Vieira De Oliveira Salerno, MD, of NYC Health + Hospitals/Elmhurst and the Icahn School of Medicine at Mt. Sinai, examined data from 819 locations across the country – representing roughly 80% of Americans over the age of 25 – spanning the years 2000 to 2020.

Researchers identified 23°C (approximately 74°F) as the temperature associated with the lowest rate of cardiovascular deaths. As temperatures deviated from this point, whether warmer or colder, the risk of death increased. However, the relationship wasn’t symmetrical. The impact of cold was far more substantial than that of heat. The study estimates that cold temperatures contributed to approximately 6.3% of all cardiovascular deaths during the study period, totaling around 800,000 deaths over two decades. In contrast, hot temperatures were linked to only 0.33% of cardiovascular deaths, or about 40,000 deaths over the same timeframe.

How Cold Impacts the Cardiovascular System

The physiological mechanisms behind this increased risk are complex. Cold exposure triggers a cascade of responses in the body, including inflammation and constriction of blood vessels. These changes can elevate blood pressure and increase the workload on the heart, potentially leading to serious cardiovascular events. Individuals with pre-existing conditions, such as diabetes, heart failure, and chronic kidney disease, are particularly vulnerable. As the prevalence of these chronic conditions rises in the U.S., Salerno notes, we can anticipate a corresponding increase in the number of people susceptible to the effects of extreme temperatures.

Beyond Individual Risk: A Public Health Challenge

This research underscores the need to broaden the scope of climate-related health planning. While much attention is rightly focused on the dangers of extreme heat, the risks associated with cold weather are often underestimated. “We tend to focus on heat-related impacts of climate change, but climate change also includes extreme cold,” Salerno explained. “We need to not only have heat-related mitigation measures, but also cold-related mitigation measures.”

The findings also have implications for healthcare systems. Hospitals and emergency medical services should prepare for potential surges in demand during colder periods. “It’s key for public health planning and also for institutions to anticipate more emergency medical service calls and in-hospital mortality during cold periods. Our systems need to be prepared for that influx of patients,” Salerno stated.

Study Details and Limitations

The research team utilized monthly temperature data and cardiovascular death rates to conduct their analysis. While this provides a broad overview, it’s important to acknowledge the study’s limitations. The leverage of monthly data, rather than daily measurements, may obscure some of the nuances of the relationship between temperature and cardiovascular health. The analysis was conducted at the population level, meaning it doesn’t provide insights into individual-level risk factors. Future research will focus on examining the correlation between temperature changes and emergency medical service activations related to cardiovascular events.

The study, titled “County-Level Temperature-Attributable Cardiovascular Disease Mortality in the U.S.,” was presented at ACC.26 and published online in the American Journal of Preventive Cardiology. Salerno is scheduled to present the findings on Monday, March 30, 2026, at 9:30 a.m. / 14:30 UTC at the Engage Stage as part of the Young Investigators Award Competition. ACC.26, taking place in New Orleans from March 28-30, 2026, will bring together cardiologists and cardiovascular specialists from around the globe to share the latest advancements in the field.

What’s Next for Cardiovascular Health and Climate Resilience?

The findings from this study are likely to prompt further investigation into the complex interplay between temperature, cardiovascular health, and public health preparedness. Researchers will continue to refine their understanding of the physiological mechanisms underlying these associations, and to identify populations most at risk. Public health officials will need to incorporate these findings into their climate adaptation plans, developing strategies to mitigate the cardiovascular risks associated with both extreme heat and extreme cold. This includes improving early warning systems, enhancing access to healthcare, and promoting public awareness of these risks. The American College of Cardiology (https://www.acc.org/) will likely continue to feature research on this topic in future scientific sessions, driving further discussion and innovation in the field.