No one needs to be told that showing up and petting a stranger’s dog can make your day, but a growing body of research suggests it could be great for your health, too.
A new field of scientific study is discovering that even brief positive experiences between people and man’s best friend can have a lasting impact, lowering stress hormones and increasing what experts sometimes call ‘the love hormone’.
In fact, there is growing evidence that even brief moments of quality time with a good dog can also help people think better.
Short, twice-weekly interactions between schoolchildren and dogs helped improve the children’s reasoning and concentration skills, positive effects that the researchers found persisted for months.
A new field of scientific study is discovering that even brief positive experiences between people and man’s best friend can have a lasting impact, lowering stress hormones and increasing what experts sometimes call “the love hormone.”
“I think it’s safe to say that animals are beneficial to our mental and physical health,” said professor of psychiatry Nancy Gee, director of the Center for Human-Animal Interaction at Virginia Commonwealth University (VCU). National Public Radio.
“We’re seeing really nice effects,” he added.
Gee’s center at VCU is part of an explosion of new research into the health-improving potential of people who interact more often with animals.
Research on the topic has expanded with funding from both the public sector, including the US National Institutes of Health, and private nonprofit organizations, most notably the Waltham PetCare Institute of Science.
However, Gee is quick to point out that “pets are not a panacea” and that many of the therapy dogs used in his group’s research have been specially selected for their well-behaved, friendly attitude and willingness to follow directions.
Also, not everyone is a dog lover, either due to allergies or simple personal preference.
“But for people who really understand, who really connect with animals,” Gee said, “they can really make a world of difference.”
Last year, a team of Australian medical researchers and psychologists reviewed 129 peer-reviewed studies on human-dog interactions finding that more than half of those studies measured positive physiological changes within people’s bodies and minds.
In particular, these studies have shown that the presence of the stress hormone cortisol plummets in people who have simply enjoyed 5 to 20 minutes with a dog. It didn’t matter, the researchers said, whether it was their pet or someone else’s.
“In addition, we see increases in oxytocin, that kind of bonding hormone that makes you feel good,” Gee told NPR.
The Australian team also found broad scientific consensus that human-dog interactions increased ‘heart rate variability’ – changes in people’s heartbeats that have been shown to be a good measure of overall improvements in health.
Higher “heart rate variability” (HVR), according to medical experts, has been linked to higher rates of relaxation, while lower HVR has been associated with major depression diagnoses and increased risk of fatal heart disease.
“What I love about this investigation,” Gee said, “is that it’s a two-way street.”
“We see the same thing in dogs,” he noted. “So the dogs’ oxytocin also increases when they interact with a human.”

Evidence has mounted that the presence of the stress hormone cortisol plummets in people who have simply enjoyed 5 to 20 minutes with a dog. Research has shown that it didn’t matter if it was your pet or someone else’s. But the best part: The dogs’ brains felt the love, too.
Gee herself has contributed to international collaborations on this research, helping scientists at the UK’s University of Lincoln with a randomized control trial studying how regular playtime with dogs could benefit school-age children.
The team looked at the effects of short interactions between young students, each aged 8 to 9, and dogs that visited their classroom about twice a week.
She and her colleagues found that students who played with dogs during the week had less stress and better “executive functioning,” meaning their reasoning skills and ability to focus improved considerably.
And those cognitive benefits did not disappear over time.
‘We actually saw [those effects] a month later,’ Gee said. And there is some evidence that [they] it may exist six months later.
Of course, as great as an impromptu encounter with a new dog in a public park or at school may be, its health benefits pale in comparison to the documented rewards of owning a true blue dog.
Another comprehensive analysis of peer-reviewed scientific studies, this published by the American Heart Associationfound that owning a dog was linked to a 33 percent reduced risk of death for heart attack survivors living alone.
The so-called ‘meta-analysis’, which took data from 10 studies that, in total, tracked the health of 3.8 million people, reduced the risk of death for stroke survivors who previously lived alone by 27 percent. .
Overall, the American Heart Association found that living with a dog reduced the chances of death overall by 24% and reduced the risk of death from heart attack by 31%.
According megan muellerprofessor of psychology at tufts university, one of the reasons dogs are so good at reducing stress and improving concentration than humans is simply because they are so good at living in the moment.
“Animals, and dogs in particular, live in the moment,” Mueller told NPR. “They are experiencing their environment with wonder and wonder all the time.”
“They’re not mentioning what happened to them earlier in the day or what they’re thinking about in the future,” he said. They are there right now.