That is the finding of a study on moderators of cardiovascular reaction to stress conducted by Karen Allen, research scientist in the UB School of Medicine and Biomedical Sciences and Millard Fillmore Hospital. Results of the study were presented for the first time at the annual meeting of the American Psychosomatic Society, held March 7-10 in Williamsburg, Va.

The research was designed to assess the effectiveness of different types of social support in helping people cope with stressful situations. Allen also set out to test the hypothesis that persons with high levels of hostility (the so-called "Type A" personality) did not respond to normal social support.

"This study indicates that in investigating the role of social support in helping to control reactions to stress, the nature of the support must be considered," Allen said. "In this study, one type of support, a pet dog, was clearly more effective in controlling physiological reactions in stressful situations than other conventional approaches."

"In addition, this study showed that individuals previously thought to be resistant to the possible benefits of social support (those high in cynical hostility), can benefit from the presence of a non-judgmental friend, i.e., a pet dog."

The investigation involved 240 couples, half of whom owned dogs and half who didn't. All persons performed three tasks used routinely by researchers to simulate stressful situations-mental arithmetic, giving a speech and placing a hand in ice water, a situation considered analogous to undergoing a painful medical procedure.

Each participant performed the tasks under one of four conditions: alone; with dog or friend (non-dog owners); with spouse and dog or friend, and with spouse only.

To measure their physiological reactions to stress, participants' heart rate and blood pressure, both systolic and diastolic, were recorded as they performed the tasks. Participants also completed standardized tests designed to determine the levels of hostility in their personalities, closeness of their marital relationship and attitude toward pets.

Results showed that under stressful conditions calling for the subject to perform a task, i.e., mental arithmetic or speech-giving, participants received the least benefit from having only their spouse present and the most benefit when just their dog was present.

The next-highest reactivity occurred when participants were alone, followed by the condition that included a spouse and either a dog or a friend.

During the cold pressor test, being alone was the most stressful for participants, while having a dog as a companion was least stressful. Under this condition, having a spouse or friend present helped moderate increases in pulse and blood pressure somewhat.

The results also showed that persons with high levels of hostility, thought to be unable to benefit from social support from other people, responded positively to the presence of a dog.