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

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 then again aged 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 reported in the Journal of Epidemiology & Community Health.

Unions described as "deteriorating", on the other hand, "were associated with worsening diastolic blood pressure."

"Changes in the quality of a marital relationship appear to predict CVD (cardiovascular disease) risk," the study authors concluded.

Little change, however, 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 better 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 would translate into actual disease.

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

"Further research needs to determine if effective marriage counselling, or when appropriate, abandoning a deteriorating relationship, has longer-term physical health benefits," said the team.