Is the Silent Danger Cold, Not Heat?

A new study presented at the American College of Cardiology's meeting last month has revealed that cold weather may have a much greater effect than hot weather on deaths from heart attack and stroke.

The study examined more than 14 million deaths from cardiovascular disease that occurred in the US between 2000 and 2020. The research evaluated data from 819 regions covering about 80% of the country's population.

The researchers determined that the ideal temperature, at which the risk of cardiovascular death is lowest, is about 23°C (73°F). Moving away from this level was found to increase the risk of death; however, the increase was much more pronounced at low temperatures.

According to the data, during the study period cold weather was associated with about 800,000 cardiovascular deaths, while deaths due to hot weather remained at about 40,000. On average, 40,000 cardiovascular deaths each year were associated with cold, while hot weather was linked to only about 2,000 deaths.

The researchers emphasize that the risk increases not only during extreme weather events but also with routine daily exposure to cold. Older adults and people with existing cardiovascular disease are considered especially vulnerable.

In conclusion, although public health discussions mostly focus on heat waves, the data show that cold weather may be the greater long-term threat to heart health.

Source: Salerno PRVO, et al. "Cold weather responsible for many more stroke and heart attack deaths than heat." Presented at the ACC.26 Annual Meeting, American College of Cardiology. Reported in Cardiovascular Business by Dave Fornell, March 26, 2026.