If you own a cat, you know the downside: ripped couches, chronic disobedience, midnight yowling. But on the other hand, a cat may be good for your heart, according to a University of Minnesota study.

Examining data on 4,435 adults, the researchers found that the relative risk of death from heart attack was 40 percent higher for those who had never owned a cat. Specifically, 3.4 percent of cat owners died from a heart attack during the course of the study versus 5.8 percent of non-owners.

Whether owning a dog confers the same benefit isn't clear; there wasn't enough data to draw any conclusions, says lead researcher and neurology professor Adnan Qureshi, who performed the study with others at the University's Zeenat Qureshi Stroke Research Center. He presented the findings in February at the International Stroke Conference in New Orleans.

Two pieces of evidence led Qureshi and his colleagues to investigate whether owning a pet can benefit one's cardiovascular health. For one thing, various social factors have previously been linked to heart health. Also, he says, there was anecdotal evidence suggesting that pet ownerhsip can reduce the risk of heart disease, high blood pressure, and related conditions.

"But does that translate to a protective effect?" he says. To find out, the researchers turned to the second National Health and Nutrition Examination Study, a large national database designed to identify risk factors for cardiovascular disease.

"If we assume that cat ownership is directly responsible for the benefits, then the most logical explanation may be that cat ownership may relieve stress and anxiety and subsequently reduce the risk of cardiovascular diseases."

The study revealed that a lower risk of heart attack was associated not only with owning a cat, but with ever having owned one. The relationship held even after the researchers adjusted for classic cardiovascular risk factors such as blood pressure, diabetes mellitus, cigarette smoking, and high cholesterol.

"If we assume that cat ownership is directly responsible for the benefits, then the most logical explanation may be that cat ownership may relieve stress and anxiety and subsequently reduce the risk of cardiovascular diseases," he says.

Although it may be tempting to conclude that getting a cat will improve your chances of avoiding a heart attack, the effect may be due to preexisting differences between cat lovers and the rest of the population. In other words, says Qureshi, the question is whether owning a cat directly reduces the risk of cardiovascular disease, or if people who own cats have personality traits that tend to protect against cardiovascular diseases independent of cat ownership.

This study can't answer that question, nor should it be construed as a recommendation to get a cat. But Qureshi wants to get to the bottom of the matter. He plans to examine more data from other studies to see whether they confirm the relationship between cats and heart health. If the relationship holds, new data may turn up other insights, such as what it is about pet ownership that may benefit people, especially those at high risk for cardiovascular disease.

Despite the uncertainties, however, it's clear that owning a cat has one thing going for it.

"If this relationship is real, then, unlike other preventive measures such as angioplasty or medications, this seems to be very low risk and may not need to be evaluated like other medical interventions," Qureshi says.

He should know. He owns a cat.