In the first controlled study of the effects of pet therapy in a random sample of acute and critically ill heart patients, anxiety as measured on a standard rating scale dropped 24 percent for those visited by a dog and a human volunteer, by 10 percent for those visited by a volunteer alone and not at all for those with no visitors. Similar results were found in measures of heart and lung function.
A separate study said heart patients shouldn’t ride roller coasters.
Kathie M. Cole, a nurse at the University of California, Los Angeles, said 76 patients with heart failure, a condition that affects an estimated five million Americans, were randomly assigned one of the three visit types. The dogs, from 12 breeds, were screened for behavior and disease before participating in the study. Some patients in the first group, Ms. Cole said, “began to smile and immediately engaged in conversation with dog and volunteer.” Their worries seemed to vanish from their faces, she said.
Besides the anxiety measurement, researchers found, patients’ levels of epinephrine, a hormone the body makes when under stress, dropped 17 percent when visited by a person and a dog, and 2 percent when visited by only a person. Epinephrine levels rose an average of 7 percent in the unvisited group in the study, which was financed by the Pet Care Trust Foundation, a nonprofit group. Pressure in the heart’s top left chamber dropped 10 percent after a visit by volunteer and dog. The same pressure rose 3 percent for those visited by a volunteer and 5 percent for the unvisited group. Pressure in the pulmonary artery dropped 5 percent during and after a visit by volunteer and dog, but rose in the other two groups.