When Nick Hansen suffered a heart attack, his physician made several recommendations as part of a recovery regimen. He told the 65-year-old Chicagoan to quit smoking, avoid alcohol, lose weight, start a walking program, go on a sodium-restricted and low-cholesterol diet – and get a dog.

Twenty or 30 years ago, that may have seemed like unusual advice. But thanks to recent medical studies, doctors are beginning to appreciate the role pets can play in increasing the chances of survival for heart attack patients.

Pet Ownership Ranks High

According to a study of how psychological factors contribute to recovery rates for heart-disease patients, pet ownership ranked highest – above even such factors as a spouse or a supportive family – in determining the patient's prognosis for long-term survival.

In that study, conducted in 1980 at Brooklyn College, only 5.7 percent of 53 pet owners, compared with 28.2 percent of 39 patients who did not own pets, died within a year of discharge from a coronary-care unit.

"The effect of pet ownership on survival was independent of the severity of the cardiovascular disease," said Dr. Erika Friedmann, who worked on the study. "That is, among people with equally severe disease, pet owners were less likely to die than non-owners."

Second Study Replicates First

Fifteen years after the first results were in, Friedmann and her colleagues replicated the original study, this time extending it to a larger number of subjects. Researchers studied 369 patients who had experienced myocardial infarctions and had ventricular arrhythmias (life-threatening, irregular heartbeats), and divided them into two groups: those who owned dogs and those who did not.

Friedmann found that 19 of the 282 patients who did not own dogs died within a year after having a heart attack. Of the 87 patients who owned a dog, only one died. The researchers concluded that dog owners were approximately 8.6 times more likely to be alive in one year as those who did not own dogs.

As in the first study, the association of dog ownership with survival could not be explained by differences in the severity of the illness. Nor could psychological, social status, or demographic characteristics account for the difference in recovery rates, Friedmann noted.

"One could argue that because dog owners exercise their animals, they are generally healthier than non-dog owners," she said. "However, when we compared physiological profiles of dog owners and non-dog owners, there were no significant differences, suggesting that the relationship itself with the animal was the key predictor of survival rates."

Researchers believe there is also evidence that pets can act as anti-arousal agents in some kinds of moderately stressful situations, that they help lower cholesterol levels, keep blood pressure down, and also help promote positive interactions with others. For heart attack patients, that may be just what the doctor ordered.