Dear Doctor Column, January 27, 2003

Question:

My job is very demanding and stressful, and I've been on high blood pressure medication for about a year. My sister, who's a geriatric nurse, told me she read about a study that showed owning a pet can help keep your blood pressure under control during times of stress. Have you heard of this study?

Answer:

Perhaps your sister was referring to the study reported at the American Heart Association Scientific Sessions in 1999, which showed that pets may play a role in taming physical responses to stress.

Dr. Karen Allen at the State University of New York at Buffalo assessed the social support effect of pets on heart rate, blood pressure, and activity of plasma renin (an enzyme that increases in response to stress and, in turn, increases blood pressure) in response to mental stress in a group of 48 male and female New York stockbrokers who were using medication to control high blood pressure.

A blood pressure reading of less than 140/90 millimeters of mercury (mm HG) is considered normal; without medication, the stockbrokers had an average blood pressure of 165/110 mm Hg. Study participants were non-smoking college graduates with no other medical conditions, made more than $200,000 a year, lived alone, and hadn't owned a pet in 5 years. They also had to be willing to get a dog or cat if they were assigned to the pet-ownership group.

Six months later, researchers found that the participants with a pet experienced half the increase in blood pressure under stress as those who were in the medication-only group. The study shows, said Dr. Allen, that if you have high blood pressure, a pet is good for you when you're under stress, and pet ownership proves especially beneficial if you have a limited support system. She also noted that many of the stockbrokers in the medication-only group acquired pets of their own after they learned the study results.

Dr. Allen has shown in previous studies that a loved pet can exert a calming influence on blood pressure and heart rate when the owner is performing standard tasks designed to induce mental and physical stress. Her research also has shown that pet ownership substitutes, in part, for human companionship and provides physiological benefits similar to that of friendship for older women who live alone.

Her earlier studies compared healthy, existing pet owners with non-pet owners; The 1999 study was the first to look at people with a medical condition, in this case high blood pressure, and how a pet can help reduce stress reactivity. Other studies involving children, AIDS patients, and Alzheimer's patients have all shown positive responses to pets, as well.

Getting a pet may be just what the doctor ordered.