Seniors and people with heart problems need to exercise more caution during cold snaps compared to heat waves, a new study says.

Folks are at much greater risk for heart attacks, strokes and other heart health problems during colder weather, researchers reported in the American Journal of Preventive Cardiology.

About 80% of heart-related deaths occur at temperatures under 74 degrees Fahrenheit, researchers found.

Overall, the study linked 1 in 16 heart-related deaths to cold weather versus 1 in 300 linked to heat.

“This may be surprising to many, but most temperature-related cardiovascular deaths are associated with cold, not heat,” said lead researcher Dr. Pedro Rafael Vieira De Olivera Salerno, an internal medicine resident at the Icahn School of Medicine of Mount Sinai in New York City.

“While heat waves are a major focus for health issues, colder temperatures are associated with far more heart-related deaths over time,” he said in a news release.

For the new study, researchers analyzed more than 14 million heart-related deaths of people older than 25 across 819 counties in the United States between 2000 and 2020.

The team compared the deaths to local temperature data, to quantify how many deaths were linked to exposure to colder weather versus higher temperatures.

Colder weather was linked to roughly 800,000 deaths over two decades, compared to 40,000 deaths attributed to warm weather, researchers found.

Results indicate that 74 degrees is the optimal temperature for heart health.

Temperatures under 74 degrees accounted for about 40,000 heart-related deaths annually, compared to about 2,000 deaths for temperatures over 74 degrees, the study says.

Cold temperature tends to increase blood pressure and heart oxygen demands, potentially increasing the risk of heart attack or stroke due to blood clots or clogged arteries, researchers said. 

“As clinicians, we see seasonal patterns in cardiovascular events, but this helps quantify how much cold exposure contributes at the population level,” Salerno said.

“This isn’t just about extreme weather. Even routine cold exposure, especially in vulnerable patients, can increase cardiovascular risk,” he said.

Salerno also presented these findings Monday at the American College of Cardiology’s annual meeting in New Orleans.