Studies show when people pet an animal, their blood pressure goes down along with stress and anxiety. That's why there are so many therapy dogs in schools, counseling centers and even in hospitals.

Taz wags his tail when he greets patients at the University of Missouri Hospital. Taz and Bruce Miller are part of a therapy dog team.

"He gets a lot of attention — haha — and he loves the attention," Miller said.

Taz is trained to provide comfort and emotional support to the patients he visits. And while no one wants to be in a hospital, Kevin Gwin's job is to make sure a stay at the University of Missouri Hospital is a positive one.

"I think sometimes patients feel isolated," Gwin said. "They get out here, it's lonely, it's boring. And the dogs are something to look forward to, and when they visit, the whole unit comes alive."

Fourteen-year-old Peyton Waldren loved having Taz visit him.

"I was just really excited because I havenʼt seen a dog in a really long time, so, it made me happy," Waldren said. "I didnʼt think about my pain, I didnʼt think about what else was gonna happen."

Therapy dogs are even in the intensive care unit at Johns Hopkins Hospital. They visit patients who are well enough to interact with the dogs.

Marlena Casey is the two-legged partner of a therapy dog team that includes Molly, a black Labrador retriever. Casey said the training is rigorous.

"We went through training for about three years, both in classes, and then alone by myself," Casey said. "And she passed her test in April."

But actual research on how these dogs impact patients doesn't exist. Megan Hosey, a psychologist, has initiated a study to see if these dogs improve patients' well-being.

"Our review of previous literature found that patients who are in settings like hospitals, nursing homes and psychiatric facilities have benefits from working with therapy animals that include improved mood, reductions in pain, improvements in heart rate and heart rate variability and, just in general, better engagement with their medical care," Hosey said.

Yet there is no hard data to prove any of this. One of the things Hosey wants to examine is if patients are more motivated to follow doctors' orders after visits by a therapy dog.

Another area is to see if patients visited by these dogs have improved moods, which could also affect their medical outcomes.

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Hosey said the study will be completed in about two years. Then she and the rest of the medical community will have data on the impact therapy dogs have on patients. (VOA)