03/04/2014 04:50 pm ET

Heart Attack Risk Is 5 Times Higher Right After An Angry Outburst, Study Finds

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Here's a good reason to keep your cool: A new study shows that the risk of heart attack increases five times in the two hours after an angry outburst.

Researchers from Beth Israel Deaconess Medical Center reviewed nine studies published between 1966 and 2013 to analyze cardiovascular risks associated with anger.

They found that risk of acute coronary syndrome (where a blocked artery leads to symptoms of chest pain or shortness of breath) and heart attack was 4.7 times higher in the two hours after a person engaged in an angry outburst, compared with other times.

It's important to note that for people who aren't at high risk for heart disease (due to smoking or high blood pressure), the overall risk of heart attack and other heart conditions associated with angry outbursts "is relatively small," study researcher Dr. Murray Mittleman, M.D., DrPH, a physician in the CardioVascular Institute at Beth Israel Deaconess Medical Center and associate professor of medicine at Harvard Medical School, said in a statement. "However, we should be concerned about the occurrence of angry outbursts with our higher risk patients and our patients who have frequent outbursts of anger."

In the study, published in the European Heart Journal, the researchers also discovered a 3.6 times higher risk of experiencing a stroke caused by a blocked artery in the brain in the time after an angry outburst compared with other times.

There was also a 6.3-fold higher risk of brain aneurysm in the hour after an angry outburst, according to one of the studies examined in the review.

People with implanted cardiac defibrillators were nearly twice as likely to experience an abnormal heart rate -- which would require a shock from their device -- in the 15 minutes after an angry outburst, researchers found.

But why does anger seem to be so bad for the heart? WebMD previously pointed out that strong negative emotions can actually affect the heart biologically. This is either by activating the body's "fight or flight response" or triggering the "stress axis," Laura Kubzansky, Ph.D., MPH, an assistant professor at Harvard School of Public Health, told WebMD.

The stress axis route is "a slightly slower response, but it activates a cascade of neurochemicals that are all geared toward helping you in the short run if you're facing a crisis," Kubzansky said.

It's not just anger that can raise the risk of heart attack -- a previous study conducted by researchers from the University of Sydney's Brain and Mind Research Institute showed that extreme stress (like from a natural disaster), as well as sudden emotional stress (like from a loved one suddenly passing away) could raise heart risks.