A new study finds that within two hours of an angry outburst, a hot-tempered person’s risk of heart attack or stroke is almost five times higher.

We’ve all lost our temper at one time or another. Now, a new study, published in the European Heart Journal, reveals that having an angry outburst may increase your risk for acute cardiovascular events, such as a heart attack or stroke, in the hours following the outburst.

What’s more, researchers report that the risk for cardiovascular problems is highest among people who more frequently lose their cool and who have existing risk factors such as prior heart problems.

Acknowledging that the absolute risk to any one individual of having heart trouble after an outburst remains very low, the researchers’ review of several studies indicated that the risk did increase considerably, compared with periods of composure.

Researchers analyzed the findings of nine studies that were conducted between 1966 and 2013 and that included more than 4,500 cases of heart attack, 462 cases of acute coronary syndrome, more than 800 cases of stroke, and more than 300 cases of heart rhythm problems.

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Researchers also found that within two hours of an angry outburst, a person’s risk of heart attack or acute coronary syndrome rose almost five-fold, the risk of stroke soared nearly four-fold, and the risk of a dangerous heart rhythm disorder called ventricular arrhythmia also spiked.

The findings show that among people with low heart risk who lost their composure just once a month, angry outbursts could result in one extra heart attack per 10,000 people per year. Among persons with a high heart risk, that number increased to four extra heart attacks.

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Researchers also learned that for those people who got angry more often, five bouts of anger a day would lead to approximately 158 extra heart attacks per 10,000 people per year among those with low heart risk, and 657 extra heart attacks among those who had high heart risk.

Dr. Sripal Bangalore, associate professor of medicine at NYU Langone Medical Center in New York, who did not participate in the study, noted that a link between angry bouts and heart problems is not surprising, since it is well known that anger is associated with increased reaction of the body’s nervous system to stress, including increases in heart rate and blood pressure.

Pointing out that the effect seems to be transient, Elizabeth Mostofsky, an instructor at the Harvard School of Public Health and the study’s lead researcher, nonetheless said, “The impact on an individual’s absolute risk of a cardiovascular event is small. However, certain people might be at higher risk.”

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Mostofsky also mentioned that although the risk of experiencing an acute heart event with any single outburst of anger is relatively low, the risk can accumulate for people who have frequent anger incidents. “This is particularly important for people who have higher risk due to other underlying risk factors or those who have already had a heart attack, stroke or diabetes,” she said.

A person without many risk factors for heart disease who has only one episode of anger per month has a very small additional risk, but a person who has multiple risk factors or a history of heart attack or stroke and who is frequently angry has a much higher absolute excess risk accumulated over time, according to Mostofsky.

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Cardiologists have long known that depression after a heart attack can have adverse effects, and that mental stress can be a risk factor for health problems. Cautioning that their findings do not necessarily show that anger causes heart attacks, but rather that there is an association between them, the researchers added that the findings were fairly consistent in all of the studies that they included in their review.