The American Heart Association put out this news release that should grab your attention if you spend any time in traffic or commuting...

People who have had a heart attack are three times more likely to report having been in traffic shortly before their symptoms began.

In a German study of patients who had a heart attack, researchers found the patients to be more than three times as likely to have been in traffic within an hour of the onset of their heart attack. The researchers also observed small but statistically significant increases in the chance that a heart attack occurred within six hours after exposure to traffic.

Driving a car was the most common source of traffic exposure, but taking public transportation or riding a bicycle were other forms of exposure to traffic. Overall, time spent in any mode of transportation in traffic was associated with a 3.2 times higher risk than time spent away from this trigger. Females, elderly males, patients who were unemployed, and those with a history of angina were affected the most by traffic.

“Driving or riding in heavy traffic poses an additional risk of eliciting a heart attack in persons already at elevated risk,” said Annette Peters, Ph.D., lead author of the study and head of the research unit at the Institute of Epidemiology, Helmholtz Zentrum Muchen, Germany. “In this study, underlying vulnerable coronary artery disease increased the risk of having a heart attack after driving in traffic.”

While this study wasn’t structured to pinpoint the reasons that being in traffic may have increased the risk of heart attack, “one potential factor could be the exhaust and air pollution coming from other cars,” Peters said. “But we can’t exclude the synergy between stress and air pollution that could tip the balance.”

Previous studies by the researchers showed that those participating in strenuous activity such as playing soccer or squash or performing heavy work such as painting overhead or snow shoveling had five to six times the risk of heart attack in the subsequent hours after the activity.

This study showed that about 8 percent of the heart attacks in the group were attributable to traffic, Peters said. “It’s just one of the factors, but it’s not a negligible number.

“We were initially surprised to observe such a strong connection between traffic and heart attacks, which we first published in 2004 based on a case series of 691 patients. It is reassuring that we were able to reconfirm this association in an extended case series. Now it’s important to find out what is behind this, whether it is air pollution or stress or both.”

The researchers also said they were surprised that women appeared to be in the higher-risk group. “Their risk is more than five times higher,” she said. “We’re not sure what the physiological mechanism is behind this; however, it might also be due to the smaller number of women as we only interviewed 325 women in five years. A larger sample of women might have provided enough statistical power to detect a more accurate assessment of risk.”