After an argument with your spouse you don't only need time to get over emotional wounds. Physical wounds take longer to heal.

Scientists have found that a half-hour argument with a loved one can slow the body's ability to heal by at least a day. In couples who have a routinely hostile relationship, the healing time may be doubled again.

This could raise the prospect of hospitals running psychological tests on patients awaiting surgery to see how long they are likely to need a bed, the researchers say. The study, in Archives of General Psychiatry, is the latest in a series of experiments carried out at Ohio State University into the relationship between stress and immunity.

Cytokines are the key elements of the immune system that stimulate healing of a wound. But if high levels are circulating through the bloodstream they cause inflammation linked with conditions such as heart disease, arthritis, diabetes and cancer, the researchers say.

The husband-and-wife team - Jan Kiecolt-Glaser, a professor of psychiatry, and Ronald Glaser, a professor of virology - tested a group of 42 married couples who had been together for an average of 12 years with a suction device that created eight tiny blisters on their arms. At the same time they were asked to talk about some characteristic they would like to change in a positive, supportive discussion.

At a second visit two months later the test was repeated, but the couples were asked to talk about an area of disagreement that had provoked strong emotions. These wounds took a day longer to heal and healed 40 per cent slower in couples rated as hostile.

Professor Kiecolt-Glaser said: "This shows why it is so important that people be psychologically prepared for their operations. Hospitals need to reduce stress prior to surgery."