Being angry, emotionally upset or engaging in heavy physical exertion may significantly increase risk of a heart attack, warns a large international study.
The researchers found an association between anger or emotional upset and the onset of heart attack symptoms within one hour.
The same was true for heavy physical exertion during the hour before their first heart attack, according to the study published in the American Heart Association's journal Circulation.
However, the association was stronger in those patients who recalled being angry or emotionally upset while also engaging in heavy physical exertion.
"Previous studies have explored these heart attack triggers; however, they had fewer participants or were completed in one country, and data are limited from many parts of the world," said study lead author Andrew Smyth from Population Health Research Institute at McMaster University in Canada.
For the study, the researchers analysed data from 12,461 patients (average age 58) participating in INTERHEART, a study consisting of patients with first-ever heart attacks across 52 countries.
The researchers said that extreme emotional and physical triggers can raise blood pressure and heart rate, changing the flow of blood through blood vessels and reducing blood supply to the heart.