If you've got a physical wound, you'd be wise to avoid arguments.

The stress of a half-hour marital spat can add a day or more to the healing process of a wound, according to a study announced Monday. And if hostility in your house is routine, count on a wound taking up to twice as long to heal.

How researchers figured this out is almost as interesting as the result.

You see, to test the healing time, you need a wound. Studies in mice have found that stress slows the process, but mice don't have much of a choice about being wounded. How do you do a controlled experiment like this on people?

Just a small wound ...

Researchers at Ohio State University managed to find 42 couples, each married at least 12 years, willing to be admitted to a clinic for two visits of 24 hours each. The visits were two months apart.

During each visit, a small suction device was used to inflict eight small blisters on their arms.

The next challenge: get the couples to fight.

The spouses were led in a positive discussion during the first visit. But in the second visit, they were encouraged to talk about things they disagreed on.

The sessions were videotaped to assess the level of hostility between a couple, while the wounds were monitored for blood flow and fluid accumulation.

"Wounds on the hostile couples healed at only 60 percent of the rate of couples considered to have low levels of hostility," said Jan Kiecolt-Glaser, an Ohio State professor of psychiatry and psychology.

The results, detailed in the Archives of General Psychiatry, are part of a long-running study aimed at learning how stress affects healing, specifically in relation to surgery.

Other evidence

"In our past wound-healing experiments, we looked at more severe stressful events," Kiecolt-Glaser said. "This was just a marital discussion that lasted only a half-hour."

In 1999, Kiecolt-Glaser and colleagues inflicted small wounds inside the mouths of 11 volunteer dental students and monitored the healing. Then six weeks later they did it again, right before final exams. The stress added 40 percent to the healing time.

In the new study, hostile couples also had 1.5 times as much interleukin-6 in their bloodstreams. This important element of the immune system is good when at the site of a wound, but not good when circulating through the body at elevated levels. Sustained high levels have been linked to inflammation that can exacerbate osteoporosis, arthritis and a host of other diseases.

The results suggest people need to be psychologically prepared for surgery, Kiecolt-Glaser says. Stress reduction could make for shorter hospital stays, lower medical bills and reduced infections.

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