Cold and the heart: an underestimated risk for cardiovascular mortality

By Elodie Vaz | Published on March 27, 2026 | 4 min read

Cardiovascular diseases are the leading cause of death in many countries. While their classic determinants are well identified, the influence of environmental factors—particularly temperature—remains insufficiently integrated into prevention strategies. Yet exposure to extreme climatic conditions may significantly modulate the risk of cardiovascular events.  

Quantifying the impact of cold on mortality

 A study published on March 24 in the American Journal of Preventive Cardiology and presented at the annual congress of the American College of Cardiology (ACC.26) aimed to comprehensively assess the association between ambient temperatures and cardiovascular mortality in the United States. It addresses a gap in large-scale data, as previous research was often limited to specific regions or populations.  

As the lead author, Pedro Rafael Vieira De Oliveira Salerno, notes: “this is the first time we have concrete figures for most of the United States, and we found that the burden of excess deaths associated with cold is substantial.”  




A population-based analysis over two decades  



Researchers analyzed data from 819 U.S. locations, representing approximately 80% of the population aged over 25. The study spans a twenty-year period, from 2000 to 2020, correlating monthly temperatures with total cardiovascular deaths.  

This approach identified an optimal temperature associated with the lowest mortality, estimated at 23°C. Variations around this threshold were then analyzed to assess their impact on mortality.  




A U-shaped relationship dominated by the effect of cold  




The results reveal an asymmetric U-shaped relationship between temperature and cardiovascular mortality. While extreme temperatures—both cold and heat—are associated with increased deaths, the impact of cold is markedly greater.  

Over the study period, cold was responsible for approximately 40,000 additional cardiovascular deaths per year, representing 6.3% of all deaths related to these conditions, with a total of 800,000 deaths over twenty years. By comparison, extreme heat was associated with around 2,000 additional deaths per year.  

These effects can be explained by several pathophysiological mechanisms: vasoconstriction, increased blood pressure, and activation of inflammatory processes—all factors that promote cardiovascular events. Older populations and patients with chronic diseases appear particularly vulnerable.  



Increased vulnerability in the context of epidemiological transition  





The study also highlights the interaction between climatic conditions and the rising prevalence of chronic diseases. “With increasing rates of chronic conditions such as diabetes, heart failure, and chronic kidney disease in the United States, we can expect a growing number of individuals to be more vulnerable to the effects of extreme temperatures,” explains Professor Salerno.  





Anticipating an underrecognized risk  





These findings call for a reassessment of the role of cold in public health policies and climate adaptation strategies. “We tend to focus on the impacts of climate change related to heat, but climate change also includes extreme cold. We need to implement mitigation measures not only for heat but also for cold,” the professor emphasizes.  

Beyond prevention, these data also have organizational implications. “It is important, both for public health planning and for institutions, to anticipate an increase in emergency service calls and in-hospital mortality during cold periods. Our systems must be prepared for this influx of patients,” he adds.  




Toward climate-informed medicine  





Despite certain limitations—particularly the use of monthly data and a population-level analysis—this study provides a robust framework for understanding the impact of temperature on cardiovascular health.   At a time when climate change is reshaping risk profiles, these findings support a more systematic integration of climatic variables into cardiovascular prevention. Such an approach could ultimately contribute to a more anticipatory form of medicine at the intersection of environment and health.  


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About the Author – Elodie Vaz
Health journalist, CFPJ graduate (2023).
Élodie explores the marks diseases leave on bodies and, more broadly, on human life. A registered nurse since 2010, she spent twelve years at patients’ bedsides before exchanging her stethoscope for a notebook. She now investigates the links between environment and health, convinced that the vitality of life cannot be reduced to that of humans alone.