Study: Extreme cold and hot temperatures elevate risk of death for heart disease patients

With cold temperatures arriving, people with heart problems need to be especially vigilant about watching the weather forecast: Research done by a Maryland doctor finds people with cardiovascular disease have increased risk of dying in extreme temperatures.

“Too hot, too cold can kill patients, especially with patients who are vulnerable with pre-existing heart conditions, including hypertension, diabetes, pre-existing heart disease,” said study co-author Dr. Haitham Khraishah, a cardiovascular disease fellow at the University of Maryland School of Medicine and University of Maryland Medical Center.

The research is published in the American Heart Association’s Journal Circulation. It’s based on 32 million cardiovascular deaths from 567 cities in 27 countries across five continents in overlapping periods ranging from 1979 to 2019.



About one in every 100 heart disease deaths is linked to extreme temperatures, the study says. The observations foreshadow a growing threat if climate change continues to warm the planet.

“Among 1,000 deaths, heat is responsible for two, cold is responsible for eight or nine. However, as our planet warms up, the number of hot days will increase and the effect of hot days will be more pronounced,” Khraishah said. “The fact that there are more cold days throughout the year than hot days makes the cold effect more pronounced than hot, but in the years to come, this is a warning that the hot effect will be much more pronounced and it will hit us harder than even cold days.”

Stephen N. Davis MBBS, chair of the Department of Medicine at UMSOM and physician-in-chief at UMMC, in a news release said “This landmark paper is a call to view climate change as a growing public health concern and highlights the need to investigate it as a potential cause of health disparities.”

As the chill of winter begins to settle in, Khraishah has a message for patients with pre-existing heart conditions.

“Consult with your doctors. Watch the weather news. Make sure to stay indoors; make sure to stay warm during this cold weather. And again — if you have any symptoms or concerns, you can always contact your doctor,” he said. “But during hot or cold, stay in stable conditions depending on the weather.”

People most at-risk are patients who’ve experienced heart failure, have coronary artery disease or have had a stroke before.

“We need patients to pay attention to day to day — day in and day out — to environmental exposures, including temperature,” Khraishah said.

A fun fact from the study: The way people adapt to their environments and temperatures around them means there’s an ideal temperature when they function best.

While the idea temperature for people in Kuwait is around 85, Khraishah said, in Baltimore, the best temperature people function at is around 78 or 79 degrees.

Kristi King

Kristi King is a veteran reporter who has been working in the WTOP newsroom since 1990. She covers everything from breaking news to consumer concerns and the latest medical developments.

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