Dogs: A Calming Influence on People with High Blood Pressure

If you're battling high blood pressure, cutting out the cheeseburgers, taking brisk walks, and shedding extra pounds are all steps you should take. But, says social psychologist Karen Allen, Ph.D., getting a pet can also help.

In a recent study, Allen, a researcher 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 non-pet-owning counterparts.

Allen and her colleagues conducted a study of 48 male and female stockbrokers who were being treated with medication to control high blood pressure. All earned more than $200,000 a year, had lived alone for at least the last five years and had highly stressful jobs.

Before the study began, researchers asked the participants to quickly count backward by 17 or try arguing their way out of a shoplifting charge. During these exercises, blood pressure levels reached an average peak way above normal – even above what doctors generally consider "high" blood pressure.

Drug Prescribed at Start of Study

At the start of the study, the brokers were prescribed the anti-hypertension drug, lisinopril. Half of the participants were randomly selected to also get a dog or cat as a house pet. Six months later, Allen and her colleagues conducted tests in the participants' homes to measure changes in blood pressure. They found that stress-induced blood pressure continued to rise in the brokers without pets.

The brokers who owned pets also had stress-related rises in blood pressure, but these rises were only half as high as those seen in the petless group. The pet-owning brokers had average systolic pressures (the first number in a blood pressure reading) that fell within the normal healthy range. Stress-related peaks in diastolic pressure (the second number in a reading) were also reduced.

Based on these findings, the researchers concluded that while the drug lisinopril helped lower resting blood pressures, pet ownership is better at helping to control stress-induced peaks in blood pressure.

Following the study, many of the participants who did not have pets decided to acquire them, Allen said. "When we told the group that didn't have pets about the findings, many went out and got them," she said. "This study shows that if you have high blood pressure, a pet is very good for you when you're under stress, and pet ownership is especially good for you if you have a limited support system."

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