Angry people beware. A person's risk of suffering a heart attack or stroke jumps significantly in the two hours immediately after an angry outburst.

US researchers analysed studies carried out between 1966 and 2013, which looked at the links between heart-related conditions and anger. They focused on nine of these studies, which included over 4,500 cases of heart attack and over 800 cases of stroke.

The researchers found that in the two hours immediately after an angry outburst, a person's risk of suffering a heart attack increased almost five-fold compared to when they were not angry.

A person's risk of a stroke increased at least three-fold, while their risk of a ventricular arrhythmia (an irregular heartbeat), also increased following an angry outburst.

The study noted that the absolute risk increased if a person already had heart risk factors and they often became angry.

"Although the risk of experiencing an acute cardiovascular event with any single outburst of anger is relatively low, the risk can accumulate for people with frequent episodes of anger. 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.

"For example, a person without many risk factors for cardiovascular disease, who has only one episode of anger per month, has a very small additional risk, but a person with 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," said Dr Elizabeth Mostofsky of the Harvard School of Public Health.

The researchers worked out that one extra heart attack per 10,000 people per year could be expected among people with good heart health who were angry just once a month. This would raise to four per 10,000 among people with poor heart health.

However, among people with good heart health who become angry at least five times a day, 158 extra heart attacks per 10,000 people could be expected. And among those who are frequently angry and have poor heart health, this would rise to 657.

The researchers said that their study shows that ‘compared to other times, there was a higher rate of cardiovascular events in the two hours following outbursts of anger'.

"It is important to recognise that outbursts of anger are associated with higher risk of heart attacks, stroke and arrhythmia. If clinicians ask patients about their usual levels of anger and find that it is relatively high, they may want to consider suggesting either psychosocial or pharmacologic interventions," Dr Mostofsky added.

Details of these findings are published in the European Heart Journal.