Scientists found that being in a strained relationship not only affected the mental health of women but also increased levels of high blood pressure, obesity, and cholesterol, all symptoms that add up to "metabolic syndrome" that can lead to heart disease. Women in tense, strained marriages are more likely than men to suffer from mental problems like depression, but also dangerous physiological conditions.

While many studies have linked poor marriages with poor health, Henry said she believes her is the first to tie in depression as a possible route through which the strain boosts the risk of metabolic syndrome. "The negativity triggers the depression, which is associated with the metabolic syndrome," said author Nancy Henry, a doctoral candidate in clinical healthy psychology at the University of Utah. This was found true, she said, only for the women in her study.

For the study, she interviewed 276 couples, median age 54, by questionnaires, asking about positive aspects of marriage quality such as mutual support and sharing, and negative aspects such as arguing, feelings of hostility and disagreeing over important issues such as kids, sex, money and in-laws.

"We found this was true for wives in this study, but not for husbands," says Henry, who was scheduled to present the findings Thursday, March 5 in Chicago during the American Psychosomatic Society's annual meeting.

Professor Tim Smith, who co-led the research, said there was good evidence that a healthy diet and regular exercise could reduce a woman's risk of metabolic syndrome as well. However, Christine Northam, a counselor for the charity Relate, said there was plenty of evidence that people in a stable, happy relationship enjoyed both good health and a longer life expectancy.