Get Healthy, Get a Dog

Harvard study makes it official: dogs are good for us.
By Twig Mowatt, June 2015

If you live with a dog, chances are you’re familiar with canine de-stressing techniques. Perhaps you’ve felt a wave of relief from burying your face in fur after a difficult day at work, or experienced a release of calming chemicals after being met with a particularly enthusiastic greeting. And maybe those daily dog walks have helped you shed a few pounds or led to some welcome social interactions with other people and their dogs. And doesn’t life seem to have more meaning because there’s a living creature depending on you?

To dog people, the emotional, physical and even spiritual benefits of canine relationships tend to be obvious. These benefits feel as real to us as the saliva-soaked tennis ball we’re holding in our hands. That’s why it can be so hard to understand why the non-dog world hasn’t caught on to all these life-altering advantages. Even worse is the fact that many people who have never lived with a dog seem to think we may be making all this up—that the only place these benefits exist is in our heads.

Science in Action

Thanks to a special report from Harvard Medical School (HMS), we now have something important to share with these nonbelievers—proof! Get Healthy, Get a Dog is the first publication to compile hundreds of research studies from around the world that document the physical and psychological benefits of dog ownership. Taken together, these studies provide the most complete picture yet of the many ways in which dogs enrich human life: from lower cholesterol and improved cardiovascular health to weight loss, companionship, defense against depression and longer lifespans.

“The most common reaction we’ve been getting from people about this report is that they are so grateful that someone has finally put into print what they’ve known intuitively all along,” said medical editor Elizabeth Pegg Frates, MD, who supervises the Lifestyle Medicine Interest Group at HMS, teaches a college course on lifestyle medicine at the Harvard Extension School, and directs the Wellness Programs at the Spaulding Stroke Research and Recovery Institute, an HMS affiliate.

The 50-page report is the result of a collaboration between HMS and Angell Animal Medical Center, a leading veterinary hospital based in Boston. Get Healthy, Get a Dog approaches the dog/human relationship as a two-way street, so half of it is devoted to the human—what the dog does for the person—and half is devoted to the dog—what the person should do for the dog. Frates tackled the former, and Lisa Moses, VMD, who heads the Pain Management Service at Angell Animal Medical Center, covered the latter, which includes sections on nutrition, exercise, training and responsible pet ownership. Moses also makes a compelling case for adopting a dog rather than going to a breeder or pet store.

“We didn’t want to create the impression that a dog is some kind of tool for achieving better health,” says Moses in explaining the dual focus. “We wanted to emphasize that it’s the relationship that provides these benefits—it’s not the pet. And for that relationship to develop and be sustained, you have to do your part.”

Physical Benefits 

Doing your part often means going for walks in the rain, sleet or snow, at all hours of the day and night. In fact, one of the primary health benefits of owning a dog is that it boosts your activity level. There have been about a dozen studies conducted on the link between dogs and human exercise, including one that compared 536 dog owners with 380 non-owners. Those with dogs were found to be fitter, thinner and less likely to have chronic health conditions, such as high blood pressure and diabetes. A study in Missouri that paired public housing residents with certified therapy dogs for five 20-minute walks a week found that participants lost an average of 14.4 pounds without changing their diets. (The report points out that most weight-loss programs and anti-obesity drug trails can’t boast such good results.)

Of course, the fact that regular exercise helps people lose weight and get healthy isn’t exactly breaking news. The insights come from the critical role the dog plays as a fitness partner—offering everything from enthusiastic encouragement to obnoxious pestering. Unlike a human partner, a dog is not going to suggest ducking out to a movie. “The dog support was always positive, while the human support could be positive (friends, family), negative (saboteurs) or inconsistent,” wrote Frates. Another reason that people tend to adhere to an exercise program if a dog is involved is the perception that the dog needs them. In one study, 72 percent of participants cited this as the reason they stuck to the activity schedule for the full 50 weeks of the trial.

“Sometimes people find that the dog becomes the excuse for taking care of themselves,” says Moses. “It may not be acceptable to them to be so self-oriented, but if it’s about the dog, then it’s okay.”

The American Heart Association (AHA) uncovered another piece of canine magic: a dog appears to help someone who is obese overcome his or her embarrassment about being seen in public doing physical activity.

It’s likely that increased exercise plus the calming effects of dogs (which we’ll get to later) contribute to lowering blood pressure. One study actually tested dog ownership as a treatment for high blood pressure. Thirty people with borderline hypertension were randomly assigned to either adopt a dog right away or defer adoption to a later date. After five months, the segment of new dog owners experienced significant declines in systolic pressure (the top number, which measures the highest arterial blood pressure). The group that had been asked to defer adoption experienced these same declines once they had taken their new dogs home and spent time with them. In 2013, the AHA went as far as to say that pet ownership “is a reasonable strategy for reducing heart disease risk.”

And there’s more good news on the cardiac front. A study of nearly 6,000 men and women in Australia found that dog owners of both sexes had lower triglyceride levels than non-owners, and male dog owners also had lower total cholesterol levels.

Emotional Benefits 

Beyond these formidable physical benefits are the psychological ones, which according to Frates “are hard to overstate.” Dogs make us feel less isolated. They pull us into a social world inhabited by other people walking other dogs. (Seventy percent of dog walks lead to at least one spoken interaction with a stranger.) And they help us meet the basic human need for companionship. Two large, long-term studies that followed people from childhood to old age found that those who were more engaged with others—whether those others were people or animals—lived longer. Those longer lives may also be more purposeful. A dog’s total dependency can make that person feel wanted and give life a sense of meaning.

Moses knows this phenomenon first hand. Her grandfather spent more than a decade as primary caretaker for his wife, who suffered from rheumatoid arthritis and cardiovascular disease. During all those years, he had a succession of dogs to care for—or was it the other way around? After his wife died, his beloved Terrier mix Lady succumbed to kidney failure. “At age 92, unbeknownst to us, he went out and adopted another dog,” Moses says. “Having a dog was the reason he got up in the morning. It was his entire life. He was a living testament to the power of the human/canine bond.”

There are other indicators that dogs are particularly helpful to older people. The HMS report cites a year-long study from Canada that found elderly dog owners to be more capable of performing daily activities, such as dressing and feeding themselves. This is likely because in attending to their animal companions, seniors are reminded to take care of themselves. They also have a structure in place, thanks to the need for regular pet meal times and walks, which reinforces their own self-care habits.

At the other end of the age spectrum, children learn important life skills from early bonding with the family dog. That bonding can lead to stronger human connections later in life, according to a Tufts University study, which also found that kids who’ve forged emotional connections to dogs have more empathy, feel more self assured and do better in social settings.

“How else would you get your kids to touch and love something?” asks Frates, the mother of two teenage sons. “For boys especially in this culture, there are very few acceptable ways of encouraging this type of bonding and intimacy.”

There is even evidence that exposure to a dog from infancy onward reduces the likelihood that even the most allergy-prone kids will develop problems. Only 19 percent of babies living with dogs developed pet allergies, compared to 33 percent of babies who grew up in dog-free homes, according to one study.  

As those babies grow up and become college students, the dog benefits continue. Several psychological studies have found that college-age adults tend to find more stress relief in turning to their dogs than in seeking comfort from parents or siblings. Still other adults were found to shake off the blues just by thinking about their dogs … which brings us to the magic of oxytocin.

Canine Rx

Having a dog can be like having your own a prescription for oxytocin with unlimited refills—except that rather than dispensing this drug, your dog incites you to release it. Also known as the “love,” “bliss,” and “bonding” hormone, oxytocin inspires positive feelings. It helps stave off depression and limit the release of the stress hormone cortisol. You can get an oxytocin infusion by petting your dog, by laughing at the silly things she does, and even by looking into her loving eyes, a conclusion confirmed by recent study

Dogs also offer an alternative to meditation sessions and yoga classes when it comes to learning the Buddhist practice of mindfulness. Every dog walk is typically an exercise in experiencing the present moment: savoring an especially aromatic fire hydrant, having a satisfying roll in the grass or interacting with a new neighbor. Dogs put us more in touch with nature and help us put aside our worries about the future and regrets about the past to focus on the here and now.

While all the information contained in Get Healthy, Get a Dog has been meticulously reviewed and objectively compiled, Moses and Frates are hardly dispassionate observers. Both say their lives have been greatly enriched by their relationships with their dogs. They do, however, come from very different ends of the dog spectrum. Moses, who shares her home with a rescue named Rudy, describes her love of canines as developing “in utero.” This was due largely to the influence of her grandfather and the fact that he treated his Beagle mix, Friday, like one of the grandchildren.

Frates, on the other hand, was terrified of dogs after being bitten on the shoulder by a Doberman. The experience, which happened when she was eight years old, was so traumatizing that she spent the next three decades crossing the street to avoid close contact with a dog, even a little one. Finally, though, it wasn’t any particular dog who changed her mind, it was her commitment to health. As a physician specializing in lifestyle medicine, Frates thought she had all the bases covered—diet, exercise, meditation. But when she took a health and longevity quiz to determine her “real” age (as opposed to her chronological one), she was surprised that one of the questions concerned dog ownership.

Intrigued by the implications, she began to review the existing literature, much of which has been summarized in this special report. She also purchased a Goldendoodle she named Reesee, from a breeder in West Virginia. “Everything has been different for me since then,” Frates says, adding that she and Reesee are regular running buddies. “When we go running, she is so happy and I’m happy because she’s happy. You just appreciate the world in a much different way.”

Frates believes that if something like the Harvard Health Report had been available years ago, she would have explored the joys of dog ownership much sooner. Now, she hopes that the report will encourage other non-dog people to reconsider their position. “We’re hoping to encourage people to take the leap of getting to know a dog,” she says. “And perhaps we’ll also be able to encourage more dog adoptions—that’s a focus that Lisa brought to the project.”

That’s because the nonprofit Angell Animal Medical Center, where Moses works, is part  MSPCA, the nation’s second oldest humane society, and has a very active adoption component. (Now that she realizes the situation for homeless dogs, Frates says she would adopt in the future.) Get Healthy, Get a Dog includes a section on “Adopting a Dog,” which provides information on determining the right breed for your home and suggestions on finding breed rescue groups and shelters. It also urges people to stay away from pet stores, where the dogs typically come from puppy mills.

Moses hopes readers will follow the report’s suggestions and reap the amazing benefits of dog ownership.

“Dogs are more important now than ever before,” she says. “Because people are living longer and so many live alone and don’t have kids. This is the moment for the human-animal bond.”

The report is available as a printed document, a PDF or both and can be purchased online at health.harvard.edu/staying-healthy/get-healthy-get-a-dog.

Twig Mowatt covered the drug war in Colombia for the New York Times and the Associated Press and now writes about animal issues. She works closely with dog rescue organizations in Puerto Rico and with GREY2K USA.