Men who bottle up frustrations about unfair treatment at work are twice as likely to have a heart attack, a study published on Tuesday suggests.
Those who express their feelings openly, for example by getting angry, have no increased risk of heart problems, said the study which warned of the dangers of "covert coping."
"Covert coping is strongly related to increased risk of hard-endpoint cardiovascular disease," said the study, published in the Journal of Epidemiology and Community Health.
The research, led by experts at the Stress Research Unit at Stockholm University, grouped men according to how they react to conflict, with reactions ranging from: saying nothing, walking away, or expressing their anger at home later.
Men who sometimes or always walked away from conflict had three times the risk of a heart attack or dying from heart disease, with overall figures showing those who avoided conflict had twice as high a risk.
By contrast, those who reacted to unfair treatment in an open way, such as talking directly to the person with whom they were in conflict or getting angry, had no increased risk of heart attack, it said.
"We all find different things stressful and symptoms of stress can vary," said Judy O'Sullivan, senior cardiac nurse for the British Heart Foundation, responding to the study.
"But the important thing is that we need to find ways of coping with it in our lives in a positive way, whether at work or home," she added.
The average age of the more than 2,700 participants was 41 at the start of the study. None had had a heart attack when screening started in 1992. But by 2003, 47 had suffered a heart attack or died from heart disease.