March 20, 2008 Happy marriage may prolong your life Play video

(NECN/ABC) - Studies show that married people tend to live longer than unmarried people, and new research provides a clue as to why this marriage benefit exists.

Researchers from Brigham Young University provided strap-on blood pressure monitors to 204 married and 99 single adults.

Participants wore the monitors for 24 hours so the doctors could track their blood pressure while they worked, played and slept.

Results revealed that happily married men and women averaged 4 points lower on their blood pressure readings than single people did.

The biggest difference came at night, when married people's blood pressure tended to dip more.

Researchers say that marriage brings health benefits because partners encourage each other to eat healthy, exercise, and visit a doctor regularly.

They also reduce stress by supporting each other through hard times.

Social singles who had a great support network of friends still did not reap the particular benefits of marriage.

But the study found that the quality of the marriage is critical.

Unhappy couples had whose blood pressure readings than single people did.

ABC's Dr. Timothy Johnson has more.