Marital rows do not just produce harsh words and hot air - they can harden your arteries too, a study suggests.
Arguing can harm men and women's hearts in different ways
But the cause of the damage differs depending on your gender, the research by University of Utah scientists involving 150 couples found.
They said arterial disease in women was linked to either partner demonstrating hostility, but in men it was linked to either showing controlling behaviour.
The research was presented to the American Psychosomatic Society meeting.
The researchers studied 150 married couples, with at least one partner in their sixties, who were all paid to participate in the study.
None had ever been diagnosed with cardiovascular disease.
Each couple was asked to pick a topic, such as money, in-laws, children, vacations and household chores - that caused disagreements in their marriage.
They were then videoed while they discussed the topic, watched by psychology students.
It was assumed such discussions were "muted" versions of what happened at home because the couples were being watched.
The comments were coded as friendly or hostile, submissive or dominant or controlling.
For example, comments such as "you can be so stupid sometimes" or "you're too negative all the time" were coded as hostile and dominant.
Participants were also given a scan to check for signs of disease.
When the results were analysed, it was found that the wives who made the most hostile comments during the discussion had a greater the degree of calcification, which indicates that plaque is building up in the arteries that supply blood to the heart.
Particularly high levels of calcification were found in women who behaved in a hostile and unfriendly way and who were interacting with husbands who were also hostile and unfriendly, the researchers found.
However, husbands who displayed more dominance or controlling behaviour, or whose wives displayed such behaviour, were more likely than other men to have more severe hardening of the arteries.
Some couples who were most hostile were referred to marriage guidance by the researchers.
None of the people with plaque build-up were classed as a medical emergency, but some had scores which were high enough for them to be advised to talk to their doctor.
Professor Tim Smith, who led the research, said: "Disagreements are an unavoidable fact of relationships.
"But the way we talk during disagreements gives us an opportunity to do something healthy."
He added: "People get heart disease for lots of reasons.
"If someone said, 'what's the most important thing I can do to protect my heart health?' my first answers would be 'don't smoke', 'get exercise' and 'eat a sensible diet'.
"But somewhere on the list would be 'pay attention to your relationships'."
British Heart Foundation head of medical information Belinda Linden said: "There is now good evidence that emotions such as depression, anger, hostility and conflict are linked with an increased risk of heart disease.
"This study focuses on how these emotions within a marital relationship might affect people's heart and circulation.
"These emotions can be triggered when relationships are strained, particularly if there are also other problems such as lack of support, or financial difficulties."
She added: "We know that pressures such as anger or hostility can release certain chemical in the body that may increase the risk of heart disease, but we still need to understand more about how this can affect our heart and circulation."