Few things are more frustrating than being stuck in traffic, and now a new study says that it may also triple your risk of having a heart attack.

The study, released Friday at the American Heart Association's Conference on Cardiovascular Disease Epidemiology and Prevention (in Palm Harbor, Fla.), adds weight to a growing body of evidence that traffic hikes heart attack risk, says lead study author Annette Peters, an epidemiologist at the Institute of Epidemiology at Helmholtz Zentrum Muchen in Munich, Germany. The reason? Not sure, Peters says. But she speculates that fine particles spewed from car exhaust pipes are likely culprits. These pollutants can penetrate lung tissue and enter the bloodstream, potentially causing clots. There is also evidence that inhaling smog speeds up the heart rate, which may also up the odds of suffering a heart attack, Peters says.

She says the risk of heart attack after being in traffic was five times higher for women and six times higher for people with heart disease, specifically a disorder known as angina (chest pain that occurs when heart blood vessels are blocked). But that doesn't mean you need to stress out any more than usual if you're in a traffic jam: she notes that if you're young and relatively healthy (read: free of heart disease), the findings translate into an added risk of close to zero.

Peters and her colleagues surveyed 1,454 heart attack survivors between the ages of 25 and 74 in Augsburg, Germany, to determine if they had been in traffic immediately before their attacks.

Approximately 1,260,000 people in the U.S. suffer from heart attacks every year, according to the American Heart Association. You can calculate your personal risk of suffering from a heart attack over the next 10 years here.

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