Winter inversion leads to more heart attacks, Intermountain study says

Benjamin Horne, Intermountain Health's director of cardiovascular and genetic epidemiology, speaks about a study he led in a press conference on Wednesday. The study showed that in Utah, there are more health care visits for heart attacks and unstable chest pain when the air quality is worse.

Benjamin Horne, Intermountain Health's director of cardiovascular and genetic epidemiology, speaks about a study he led in a press conference on Wednesday. The study showed that in Utah, there are more health care visits for heart attacks and unstable chest pain when the air quality is worse. (Emily Ashcraft, KSL.com)


Save Story
Leer en español

Estimated read time: 4-5 minutes

This archived news story is available only for your personal, non-commercial use. Information in the story may be outdated or superseded by additional information. Reading or replaying the story in its archived form does not constitute a republication of the story.

MURRAY — Inversion in the winter and wildfires in the summer don't cause heart attacks — but they can trigger them.

Each year in Utah there are more health care visits for heart attacks and unstable chest pain when the air quality is worse, according to an Intermountain Health study.

Benjamin Horne, Intermountain's director of cardiovascular and genetic epidemiology and lead author of the study, said at a press conference on Wednesday that doctors see a "rapid increase in admissions to the hospital from people with chest pain" when there is an elevated fine particulate air pollution, or PM2.5, from wildfire smoke in the summer.

For days with poor quality due to winter inversion, the data looks different, he said. Doctors see an increase in heart attacks, often on the day inversion reaches high levels.

The study ran from 1999 to 2022 and included more than 22,000 heart patients at 11 hospitals and air quality monitoring stations between Ogden and Provo. It will be presented this weekend at an American Heart Association conference.

Why is winter inversion so bad for heart health?

Horne said while air pollution can trigger heart problems, it is not around long enough to cause them. He said it can cause clotting that can cut off blood supply in arteries that have been narrowed over decades.

He said there is about a 10% increase in risk for heart attacks for everyone when the air quality is at an orange-level air quality index, which is categorized as unhealthy for people in sensitive populations, compared to the green index during the winter. Although they didn't see a significant increase in the summer for heart attacks when wildfire smoke causes similar poor air quality, he said there is a 45% increase in risk for hospitalization due to chest pain in the summers.

Horne hypothesized that it is harder for people to decide to go to the hospital with chest pain in the winter because they are not expected to be outside and moving; therefore, the pain may be easier to ignore.

"If it's not sudden, crushing chest pain like a heart attack, where you just can't breathe … people might sit at home and think, 'Well, it's cold and snowy outside, maybe I don't want to go to the hospital and the pain's not too bad,' and they think about it for a week or two and then they end up going to the hospital," he said.

Horne said they don't know if wildfire smoke is less of a concern than inversion because of the type of pollutant, pattern of exposure, distance from the source or just how people react in the different seasons. In the 23-year study, he said researchers found wildfire smoke was not much of a concern for health until about 2012.

What should Wasatch Front residents do?

Horne explained Utah's mountains trap pollutants and smoke in the air for longer, so there is a higher risk of health problems from poor air quality.

"We don't need to panic about it, but it's something to be aware of," he said.

Not everyone is at risk for a heart attack from air pollution; Horne said usually people coming in with chest pain or a heart attack are people with underlying coronary disease, whether or not they already received a diagnosis.

He said people should evaluate their risk for heart problems ahead of the inversion season and consider their cholesterol, blood pressure and body mass index along with health history like diabetes, smoking and family members with heart disease and heart attacks before age 55.

Those who are at risk should watch the air quality and try to stay inside when the air quality is poor — especially for exercise, which increases the amount of air they are inhaling — and take their prescribed medications.

Horne said the chest pain people should be aware it can happen even without exercise or with low-intensity exercise. He said people can still function and sometimes don't seek medical attention until up to two weeks later.

Horne also encouraged health care providers to be aware of the increased risk of chest pain due to wildfire smoke and inversion, and to send people to the hospital as soon as possible if they complain of chest pain.

Most recent Health stories

Related topics

UtahSalt Lake CountyHealthEnvironment
Emily Ashcraft is a reporter for KSL.com. She covers issues in state courts, health and religion. In her spare time, Emily enjoys crafting, cycling and raising chickens.
KSL.com Beyond Business
KSL.com Beyond Series

KSL Weather Forecast

KSL Weather Forecast
Play button