That is the conclusion of scientists at a conference of the American Heart Association, who found that New York stockbrokers who owned pets had lower blood pressure in stressful situations than their petless counterparts.

They presented the findings of a study that looked at the stress response of 48 stockbrokers who were taking medication to control high blood pressure.

Half of them owned either a car or a dog, and their blood pressure consistently remained lower during a series of stressful situations.

Animal boom

Karen Allen, a research assistant professor of medicine at the State University of New York in Buffalo, said the findings had had an impact on the study group.

"When we told the group that didn't have pets about the findings, many went out and got them," Allen 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." All of the study participants had lived alone for more than five years.

The stockbrokers were all taking lisinopril, an angiotensin converting enzyme (ACE) inhibitor - a standard treatment for high blood pressure.

The researchers assessed changes on heart rate, blood pressure and levels of a stress enzyme in response to a set of tests designed to put the stockbrokers under pressure.

These included performing mental arithmetic, counting backwards from 17 as fast as possible and giving a five-minute speech to talk their way out of a shoplifting charge.

Under pressure

Those with pets had them in their company during the tests - and only suffered half the increase in blood pressure of those without.

The findings add to a growing body of evidence that having a pet can improve human health.

"For over a decade I've been studying the effects of pets on people's reactivity to stress - measured by heart rate and blood pressure responses to mental and physical stress," Ms Allen said.

"We've shown over and over that it's beneficial to be with a pet when you're under stress."

Complementary therapy

A spokeswoman from the Society of Companion Animal Studies said that although pets could not replace standard medication, they could offer additional benefits.

"There has been considerable evidence to suggest that stroking a pet or even just having a pet can reduce stress," she told BBC News Online.