Cold wave turns silent killer: Study finds higher death risk than heat

By Admin

26 Mar, 2026

Most people instinctively fear heatwaves and scorching summer temperatures. However, far fewer consider a cold morning a potential medical emergency. A new study suggests that this perception needs to change. Dropping temperatures may be far deadlier for the heart than rising ones, and the scale of the damage is much larger than previously understood.

Researchers analysed monthly temperatures and cardiovascular deaths across 819 locations in the United States, covering roughly 80% of the population over the age of 25. The data spanned two decades, from 2000 to 2020. The findings, published on March 24 in the American Journal of Preventive Cardiology, reveal that colder temperatures are linked to significantly higher cardiovascular death rates compared to heat.

Cold Weather Linked to Higher Death Risk

The study found that the temperature associated with the lowest rate of cardiovascular death was around 23°C. Death rates increased as temperatures moved away from this level in either direction, but the rise was far steeper on the colder side.

Cold weather accounted for roughly 40,000 excess cardiovascular deaths every year during the study period, which translates to about 6.3% of all cardiovascular deaths. Over the two decades analysed, this added up to nearly eight lakh deaths.

In comparison, hot weather was linked to roughly 2,000 excess deaths per year, or about 0.33% of all cardiovascular deaths. This represents a dramatic twenty-to-one difference. While heat certainly poses risks, the data clearly indicates that cold kills far more.

“This is the first time we have actual numbers for most of the United States, and we found the burden of excess deaths associated with cold is quite substantial,” said Pedro Rafael Vieira De Oliveira Salerno, lead author of the study.

Why Cold Is More Dangerous for the Heart

When temperatures drop, the body attempts to conserve heat. This triggers physiological changes such as inflammation and constriction of blood vessels. These reactions can significantly increase the risk of adverse cardiovascular events.

Narrowed blood vessels raise blood pressure and force the heart to work harder. For individuals with existing heart conditions, this added strain can become life-threatening.

People who are older or have chronic conditions like diabetes, heart failure, or kidney disease are significantly more vulnerable to these effects. Their bodies are less capable of adjusting to sudden temperature changes, making cold exposure particularly dangerous.

Climate Change and Cold-Related Risks

Public health discussions around climate change often focus on extreme heat. However, researchers warn that cold weather remains a serious and underestimated threat. Climate change can also lead to sudden cold spells, which may increase health risks for vulnerable populations.

As rates of chronic conditions such as diabetes, heart failure, and chronic kidney disease continue to rise, the number of people susceptible to extreme temperatures is also expected to grow. This increases the importance of preparing for both heatwaves and cold waves.

Implications for Public Health Systems

The study highlights the need for improved public health planning. Hospitals and emergency services may face higher demand during cold periods due to increased cardiovascular events. Authorities and healthcare systems should anticipate this influx and strengthen preparedness measures.

Cold weather safety awareness, improved housing insulation, accessible heating, and targeted protection for high-risk individuals can help reduce the impact.

A Silent Threat That Needs Attention

The next time a cold front sweeps in, it may be worth treating it with the same caution as a heatwave. While heat often grabs headlines, cold temperatures quietly place enormous strain on the heart. The data suggests that cold weather is not just uncomfortable   it can be a silent killer.