POSITIVE EVENTS OUTWEIGH STRESS IMMUNITY THRIVES ON SMALL PLEASURES.(MAIN)

Byline: DANIEL GOLEMAN New York Times

The small boost to the immune system offered by a pleasant event can persist as long as two days, while the negative effects of a stressful encounter mainly take their toll in one day, according to new findings.

While stresses like a conflict at work can make people more vulnerable to infectious disease, so can missing customary pleasures like getting together with friends, the studies show. The findings add to the growing evidence for the health consequences of day-to-day events.

``Positive events of the day seem to have a stronger helpful impact on immune function than upsetting events do a negative one,'' said Dr. Arthur Stone, a psychologist at the medical school of the State University of New York at Stony Brook, who did much of the new research.

In a study of 100 men tracked daily for three months, Stone found that stresses like being criticized at work weakened immune function on the day they occurred.

But events like a pleasant family celebration or having friends over enhanced the immune system for the next two days. The findings will be published in Health Psychology later this year.

``Having a good time on Monday still had a positive effect on the immune system by Wednesday,'' Stone said. ``But the negative immune effect from undesirable events on Monday lasts just for that day.''

Because the study involved only ordinary pleasures and stresses, the results may not apply when life becomes extremely stressful.

Each evening during the study, volunteers filled out an evaluation of the ups and downs of their day. Daily samplings of their saliva allowed researchers to monitor how effective their immune systems were in producing antibodies to a rabbit protein they took in capsule form each day.

Their rate of antibody activity ``offers an analogue of how the body reacts to a pathogen such as a cold virus,'' Stone said.

Among the men in the study, the biggest setback to immune function was caused by work problems from criticism by one's boss and frustrating or irritating encounters with fellow employees, and by feeling pressured by looming deadlines or a heavy workload.

Other sources of irritation leading to lowered immune function were burdensome chores like irksome errands or annoying home maintenance tasks.

The greatest improvement of the men's immune systems was from pleasant social activities or pursuing leisure activities like fishing or jogging. The range of stress measured was similar to that in an earlier study by Stone in which 79 men chronicled their daily ups and downs for 84 days.

In that study volunteers also filled out a checklist each evening of any medical symptoms they might have had that day.

Whenever the men reported cold symptoms, ``we found that there was an increase in undesirable events from three to five days before the cold becomes noticeable, and a dip in desirable events for those days,'' Stone said. ``That covers the incubation period for the cold,'' which is 24 to 72 hours.

A surprise in the study was that having a drop in the usual number of pleasant events more strongly predicted susceptibility to a cold than did a jump in stressful events, Stone reported last month at the annual meeting of the Society for Behavioral Medicine in Boston. Similar findings have been reported by a research team in Britain.