A wife's stress could have important implications for her husband's blood pressure, according to a recent study conducted at the University of Michigan in the US.

"We were particularly fascinated that husbands were more sensitive to wives' stress than the reverse especially given all of the work indicating that wives are more affected by the marital tie," says lead author Kira S. Birdett.

This holds true particularly in difficult marriages, and looking at the effects of negative relationship quality on health, the research team found it was hard to recognize them upon individual examinations.

Observing the couple interact together proved a more effective way of discerning stresses that could be affecting blood pressure, according to the researchers.

"An individual's physiology is closely linked with not only his or her own experiences but the experiences and perceptions of their spouses," says Birdett.

When it's a question of marriage and health, looking at the couple as a whole could be more important than examining each individual, say the researchers after examining 1,356 married and cohabitating couples, middle-aged and older.

Using systolic blood pressure as a gauge, they conducted psychosocial and biomeasure assessments on their participants between 2006 and 2012.

The health effects of difficult marriages were twofold yet varied by gender, according to the study.

A poor quality marriage was an indicator of high blood pressure when both members of the couple admitted things weren't going well.

The researchers concluded that relationship quality has a direct effect on cardiovascular health and that it moderates the effect of stress.

The study, published in the Journals of Gerontology, supports another recent study that was conducted at the University of Pittsburgh in the US linking cardiovascular health to marriage.

"Growing evidence suggests that the quality and patterns of one's social relationships may be linked with a variety of health outcomes, including heart disease," said Dr. Thomas Kamarck, professor of psychology and Biological and Health Program Chair in the University of Pittsburgh Kenneth P. Dietrich School of Arts and Sciences.

The Pittsburgh research team, whose study was published in the journal Psychosomatic Medicine, also found that relationships should be looked upon as a point of assessment by healthcare professionals.