Men whose marriages grow stronger over the years have healthier cholesterol and blood pressure than peers whose unions fall apart, said a study Monday that hinted at unexpected health perks of relationship counselling.

Researchers got more than 600 men in Britain to rate the "quality" of their marriage at two points in time -- when their child was three, and when they were nine.

The men could describe their union as consistently good, consistently bad, improving, or deteriorating.

Another 12 years later, the team measured the participants' health.

They analysed such measures as blood pressure, resting heart rate, weight, cholesterol, and blood sugar -- potential risk factors for cardiovascular disease.

Men who had described their marriages as "improving" had better cholesterol readings and a healthier weight years later, the team found.

"Deteriorating" unions, on the other hand, "were associated with worsening diastolic blood pressure."

Little change was noted for men who had reported being in a consistently good or consistently bad marriage, said the team, and speculated this may be due to "habituation" to their situation.

The researchers warned their study was merely observational and could not show conclusively that an improving marriage results in improving health.

But assuming this was the case, "then marriage counselling for couples with deteriorating relationships may have added benefits in terms of physical health over and above psychological well-being," the authors wrote.

Given that the men were still relatively young when taking part in the study, it is too early to know how their relative health risks noted would translate into actual disease.

Previous research had already shown married men to have a lower risk, on average, for cardiovascular disease such as heart attack or stroke.