Being with your dog makes you feel good. Dr. Sandra Barker is trying to find out why. Dr. Barker, a professor of psychiatry and director of the School of Medicine Center for Human-Animal Interaction at Virginia Commonwealth University, studies what happens inside our bodies when we interact with dogs.

Sandra Barker: We’re trying to find out what’s really physically going on, is there a physiological benefit that folks are getting? No one’s ever looked at the brain waves before with human- animal interaction.

Barker talked about her 2009 study, in which people’s brain waves were tested before and after spending time with a dog.

Sandra Barker: We saw an increase in the theta frequency and the alpha frequency. Those are the frequency bands and the activity that we would expect to see with relaxation.

Dr. Barker added that her team also measured a decrease in cortisol – the human stress hormone – after her subjects interacted with a dog.

Sandra Barker: We saw similar patterns in the systolic blood pressure, and we also saw it where they reported what their own level of anxiety of stress was, and they were all very similar patterns.

Dr. Barker believes that much larger scale studies are needed to find out more about how animals – like therapy dogs – can make an impact in a clinical setting. But, she said,

Sandra Barker: To find any type of impact, particularly with an intervention like this that is low cost and easily accessible was a very positive finding.

Dr. Barker added that people had the same measurable response, whether they interacted with their own trusted dog, or an unfamiliar research dog – a preliminary finding she said could be useful to health experts and patients. She then talked about another study she conducted at the National Institutes of Health (NIH) Clinical Center

Sandra Barker: We were interested in seeing the effect of that animal assisted therapy oN physiological and psychological distress in cancer patients who were referred for pain and palliative care.

She found that cancer patients had measurable decreases in symptoms of depression and feelings of tiredness after interacting with research dogs, as much as after interacting with a human therapist for the same amount of time. She underscored how significant this was, because this test group – while small – was quite ill. But, she also offered a caveat.

Sandra Barker: Most of these studies are giving us preliminary information that there’s an association between, say, decreased depression and interacting with a companion animal, but do we know that it was the dog that caused that decrease? No, we don’t. So we really need larger scale studies. So funding is, to me, the biggest challenge.

She added that, in 2009, the Eunice Kennedy Shriver National Institute of Child Health and Human Development offered a line of funding for animal-human interaction research concerning children. Once the financial challenge is met, Barkers said, there are also technical challenges. For instance: in medical trials, you can give a subject a placebo pill, so s/he doesn’t know who’s gotten the ‘real’ dose of medication. In Barker’s line of work, that’s not possible:

Sandra Barker: It’s really tough to blind somebody to a dog.