Just a 12-minute visit with a dog improved the heart and lung function of heart-failure patients, a new study has found.

The Study

Researchers randomly assigned 76 heart-failure patients between the ages of 18 and 80 to one of three groups. One group (26 patients) received a visit from a dog and a volunteer, the second group (25 patients) received a visit from a volunteer alone and the third group (25 patients) did not receive a visit at all.

Each visit lasted 12 minutes, during which time the dog would sit close enough to the patient for him/her to pet and/or talk to the dog.


Anxiety scores fell 24% for people in the group that received a visit from the dog team, but only 10% for the participants who were visited by a human volunteer. The anxiety scores for the patients who received no visit were unchanged.

There were also reductions in the stress hormone epinephrine in the groups that received visits. The level of epinephrine dropped an average of 17% in the group visited by the dog and 2% in the group visited by a volunteer, but rose 7% in the control group.

Systolic pulmonary artery pressure, a measure of pressure in the lungs, dropped 5% during the dog visit and another 5% after the visit. It rose in the other two groups.


Animal-assisted therapy has previously been shown to lower blood pressure, heart rate and cardiovascular risks. It has also been shown to reduce anxiety, isolation and fear of procedures as well as improve social interactions in hospitalized patients.

However, lead author Kathie M. Cole, a clinical nurse at the University of California at Los Angeles Medical Center, says, "There have been no randomized trials of the effects of animal assisted therapy done in acute and critically ill patients hospitalized with heart failure."

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