Risk of Fatal Heart Attack May Double on Days of Extreme Heat and Bad Air Quality: Study

The combination of extreme heat waves and high particulate air pollution – found in the unprecedented wildfire smoke that has blanketed many parts of the U.S. this spring and summer – may double your risk of a fatal heart attack. 

Days with cold snaps and high levels of fine particulate pollution could also raise your risk, but to a lesser extent.  

That’s according to findings in a new study published in the American Heart Association journal Circulation, which showed that women and seniors are more affected. 

With climate change resulting in more frequent and longer extreme temperatures, combined with the rise in smoke events “we're going to have more of these days when we have the two things together,” Joel D. Kaufman, M.D., a physician, epidemiologist and professor of medicine at the University of Washington tells The Messenger. 

The study adds to the evidence that air pollution alone is linked to a higher risk of fatal heart attacks, and that extreme heat on its own is also linked to an increased incidence of death caused by a cardiovascular event, he said. 

But this research looked at when both occur simultaneously, revealing that “the two things together are worse than either thing alone, and it seems the two things are  adding up to more than the sum of the parts,” Dr. Kaufman said. 

“Instead of it being a double whammy, it's more like a triple whammy,” he said, noting that the increased threat of a heart attack continues “for a few days” after exposure to the mix of high heat and air pollution. 

 “People need to be careful,” he said.

Scientists wondered about the impact of extreme temperatures combined with days of high fine particulate pollution on the rate of fatal heart attacks.  

To investigate that question, Yuewei Liu, M.D., Ph.D., an associate professor of epidemiology in the School of Public Health at Sun Yat-sen University in Guangzhou, China, and his colleagues analyzed more than 202,000 heart attack deaths between 2015 and 2020 in Jiangsu province. 

The researchers found that days that had either sizzling heat, extreme cold or high levels of fine particulate matter (PM_2.5) air pollution were significantly associated with the risk of death from a heart attack, especially in women and older adults.

When the weather was between 82.6 and 97.9 degrees Fahrenheit, the risk of fatal heart attacks increased 18%. During a heat wave of four days and temperatures between 94.8 and 109.4 degrees Fahrenheit, that risk was 74% higher. 

Colder temperatures were also associated with increased fatal heart attacks, but to  a lesser extent — the risk increased increased to 12% during 3-day cold snaps with temperatures ranging between 27 and 37.2 degrees Fahrenheit. 

But the “triple whammy” as Dr. Kaufman noted — when risk of a fatal heart is doubled –  was shown when days of sultry heat waves combined with high levels of fine particulate pollution.

The researchers estimated that up to 2.8% of heart attack deaths may be attributed to the combination of extreme temperatures and high levels of fine particulate pollution.

“We need to be working together as a society to try to combat climate change because that's sort of the underlying feature of both of these risk factors,” Dr. Kaufman said. 

To reduce risk, people need to heed to weather warnings, stay inside in an environment with clean air and air conditioning, and wear a well-fitted K95 or KN95 mask if going outdoors is necessary, he added. 

It’s unknown “if and how co-exposure to extreme temperatures and fine particulate pollution might interact to trigger a greater risk of death from heart attack,” Dr. Liu said in an American Heart Association press release.  

For much of the spring and summer, North America has been ravaged by wildfire smoke, which even without extreme heat puts people at a higher risk of developing cardiovascular issues, including sudden cardiac arrest and heart attacks. 

In Canada, a record-setting 20 million acres of land have burned, making this the most destructive wildfire season ever recorded, according to NPR. 

Wildfires now burning in Oregon come during a summer with historically high temperatures. 

The first week of July saw the planet experience its hottest day ever recorded. Warmer and drier summers lead to increasingly severe wildfire seasons, according to the Center for Energy and Climate Solutions.