According to a study in the European Heart Journal, a single angry outburst can have immediate adverse effects. That’s because anger causes an increase in blood pressure and a release of the stress hormones adrenaline and cortisol. Indeed, the risk of a heart attack or angina is nearly five times higher in the two hours following an anger outburst than at other times, and the risk of stroke is four times higher. Let’s not get too carried away with this though, because at any given moment the risk of a heart attack or stroke is very low, so even a five fold increase in risk isn’t that great. To put the numbers into perspective, researchers estimate that if 10,000 healthy people have one anger outburst a month over a year, one of them will suffer a heart attack or a stroke as a result of the outburst. Among people who have other risk factors such as smoking, being overweight, high blood pressure or high cholesterol, there would be four cardiovascular events over a year with one monthly outburst. But among people who get angry more often, which is not an unusual scenario, the risk rises significantly. For example, if 10,000 people who also have other risk factors have five angry outbursts a day, some 600 of them will have a heart attack or stroke.