Leading a happy married life can help improve health, according to a new 20-year-long study conducted by researchers from the University of Nebraska- Lincoln.

Researchers established a link between marital happiness and physical health claiming that relationship-building activities like date nights with a spouse could improve health. Better health can in-turn induce bliss in the relationship.

Co-author Dr Cody Hollist, a marriage and family therapy expert at the University of Nebraska-Lincoln in the U.S., said happiness and health are two sides of a coin.

"There is no way to tease out whether good marriages lead to good health or whether bad marriages make you sick. But it is clear that marital quality and health run in tandem,' Hollist said in an official statement.

The study is published in the Journal Marriage and Family.

The researchers arrived at the conclusion after observing 1,681 married people over the course of 20 years. They studied the responses of detailed surveys conducted six times during the two-decade period.

In order to study the health effects of the participants, the scientists divided the group in two - one cohort comprised of people aged 18 to 39 and the other had people aged 40 to 55. They compared the advantages and disadvantages of healthy and troubled marriages.

Some of the findings from the study:

 - A strong relationship between good health and marital happiness was observed in both age groups.

 - In the beginning of the study, the younger group was found to have better health, but revealed marital problems and less happiness than the other group.

 - The relationship between increased marital happiness and improved health was stronger for the younger group.

  - The older group's marital problems decreased over time due to improved health.

"We wanted to compare the health trajectory with the happiness trajectory," Hollist said. "As health worsens, do their marriages stay stable? What we found is that there's a relationship between health and happiness for both age groups. If their health is good, their happiness is up."

However, one surprising finding of the study was that participants who were struggling with their marriage in the beginning of the research showed improved health as time passed.

 "Stressful circumstances can be a wake-up call for some as it can motivate healthier and more adaptive pathways of behavior over time," Hollist said.