Anger increases the risk of heart attacks, and may trigger them, according to new US research, which indicates people are at higher risk of a heart attack about two hours after a temper outburst.

And while the risk is relatively low if you only rarely lose your temper, if you are venting on those around you several times a day you significantly increase your chances of heart attack or stroke.

Science is still not clear on the precise physiological changes that lead to the higher risk, but those with a history of heart disease are particularly susceptible, according to a BBC report.

Risk Is Cumulative

In the two hours following an anger outburst, the risk of heart attack increased by five, and the risk of stroke increased by more than three, data from nine studies and involving thousands of people suggests.

The Harvard School of Public Health researchers say at a population level, the risk with a single outburst of anger is relatively low - one extra heart attack per 10,000 people per year could be expected among people with low cardiovascular risk who were angry only once a month, increasing to an extra four per 10,000 people with a high cardiovascular risk.

But the risk is cumulative, meaning temper-prone individuals will be at higher risk still.

Five episodes of anger a day would result in around 158 extra heart attacks per  10,000 people with a low cardiovascular risk per year, increasing to about 657 extra heart attacks per 10,000 among those with a high cardiovascular risk.

Chronic Stress To Blame?

Experts know chronic stress contributes to heart disease, partly because it can raise blood pressure but also because people may deal with stress in unhealthy ways - by smoking or drinking too much alcohol, for example.

It is not clear how the physiological mechanisms work, the researchers say, but suggest learning to cope with high pressure situations by exercise, yoga or meditation may help.