Want to lower your blood pressure? Ward off depression? Cut down on the number of visits to your doctor? Improve your survival rate after suffering a heart attack?

Maybe you need a dog or cat in your life. Then again, maybe you don't.

Dr. Karen Allen, formerly a research scientist in medicine at the State University of New York at Buffalo, found that stockbrokers with hypertension who adopted a cat or dog had lower blood pressure readings in stressful situations than did their pet-less counterparts.

Allen and her colleagues looked at 48 male and female stockbrokers who were using medication to control high blood pressure. All earned more than $200,000 a year, lived alone, and had highly stressful jobs.

Half of the subjects were randomly selected to adopt a dog or cat at the beginning of the study. Later, in stress tests measuring changes in blood pressure, the stockbrokers without pets registered twice the stress response as those who had a pet in the room.

Allen, who presented her findings at the 1999 annual meeting of the American Heart Association, said the results were so striking that many of the study participants who did not have pets decided to acquire one after the study.

Allen says she is not certain just what happens physiologically. "There are lots of theories, but we honestly don't know why pets lower blood pressure. We suspect that having something on your side, something you can always count on that is non-judgmental, psychologically creates a beneficial atmosphere."

For nearly 25 years, research has shown that living with pets appears to provide certain health benefits. Heart attack patients with pet companions survive longer than those without, according to several studies. Male pet owners have lower triglyceride and cholesterol levels than non-owners, according to Australian researchers.

Even more interesting are the psychosocial effects, according to Lynette Hart, PhD, associate professor at the University of California at Davis School of Veterinary Medicine. "Studies have shown that Alzheimer's patients have fewer anxious outbursts if there is an animal in the home," she says. "Their caregivers also feel less burdened when there is a pet, particularly if it is a cat, which generally requires less care than a dog."

In the elderly, pets can be a great source of comfort and joy. Walking a dog or just caring for a pet, for those who are able, can provide exercise and companionship. In fact one insurance company, Midland Life Insurance Company of Columbus, Ohio, asks clients over the age of 75 if they have a pet as part of their medical screening. Garth Garlock, spokesperson for the company, said pet ownership often helps tip the scales in favor of older clients looking for life or long-term care insurance.

In addition, many people who are vulnerable to depression or anxiety suffer less if they have a pet than do those living without pets. Judith Siegel, PhD, published a study in the May 1999 journal