FRIDAY, Feb. 8 (HealthDay News) -- Experts say the secret to a long marriage is communication, and new research now notes it's also the key to a long life.

A lengthy study of Midwestern couples finds that those who felt free to express their feelings lived longer than the perennially resentful. The couples with the most unexpressed anger died the earliest.

"The worst thing to do is to keep it in, not talk about the problem, brood about it, and be continuously angry," said study author Ernest Harburg, professor emeritus at the University of Michigan School of Public Health. "Not talking about the problems in your close relationship is not good for your longevity."

The findings may seem obvious, but Harburg said previous research hadn't pinned down a connection between lifespan and level of marital communication. It's important, he said, to confirm what seems to be so.

Harburg and his colleagues have been following 192 couples from the small town of Tecumseh, Mich., for 17 years. The study, published in the January issue of the Journal of Family Communication, examines what happened to them between 1971 and 1988.

About 14 percent of the couples were defined as "anger-in" types, meaning both spouses developed resentments and failed to resolve problems. "They don't talk about the problem, and when they do, they just start fighting again," Harburg said.

After the mortality rates among the participants were adjusted for the impact of things like heart disease and smoking, the "anger-in" couples still died earlier than couples who handled anger in other ways.

Of the 192 couples studied, both spouses in 26 pairs suppressed their anger; there were 13 deaths in that group. With the remaining 166 couples, there was a total of 41 deaths. Both spouses died in 23 percent of the mutual suppression couples during the study period, compared to 6 percent of the other couples.

The better approach, Harburg said, is to work together. "You listen, you don't interrupt, you hear the other person, you talk back and forth. And then you use your imagination, resolve the problem and come to some kind of consensus."

Still, the findings did turn up some evidence that mutual open communication might not be entirely a good idea. The couples who seemed to live the longest were those in which the man expressed his anger and the wife held hers in.

Janice Kiecolt-Glaser, director of the Division of Health Psychology at Ohio State University College of Medicine, said it's clear that marital interactions affect the body. "We know that couples who are nasty or hostile with each other when discussing disagreements showed larger increases in stress hormones and greater dysregulation of immune function as a consequence," she explained.

Kiecolt-Glaser and her colleagues published a study in which they found that small blister wounds on a forearm took two days longer to heal in couples who were hostile to each other.

While the new study isn't as complete as it could be, Kiecolt-Glaser said, it does show "the importance of good communication that is consistent over time."

Harburg agreed. "If you're committed to using your intelligence and your creativity to stay in the relationship and solve the problems, then you'll get through all the rough patches," he said.

More information

Learn more about stress and the body from the American Institute of Stress.

SOURCES: Ernest Harburg, Ph.D., professor emeritus, University of Michigan School of Public Health and Psychology Department, New York City; Janice Kiecolt-Glaser, Ph.D., Division of Health Psychology, Ohio State University College of Medicine, Columbus; January 2008 Journal of Family Communication

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