By Dr. Karen Shaw Becker
A recent Swedish study demonstrates that dog parents have a lower risk of death from heart disease and other conditions than people without dogs.1
Study Shows Dog Ownership Is Especially Health-Promoting for People Who Live Alone
The study involved over 3.4 million individuals between the ages of 40 and 80 who had no prior cardiovascular disease as of 2001. The goal of the research was to determine whether dog owners had a different risk of cardiovascular disease and death than non-dog owners. According to Mwenya Mubanga, a Ph.D. student at Sweden's Uppsala University and co-author of the study:
"A very interesting finding in our study was that dog ownership was especially prominent as a protective factor in persons living alone, which is a group reported previously to be at higher risk of cardiovascular disease and death than those living in a multi-person household.
Perhaps a dog may stand in as an important family member in the single households. The results showed that single dog owners had a 33 percent reduction in risk of death and 11 percent reduction in risk of cardiovascular disease during follow-up compared to single non-owners. Another interesting finding was that owners to dogs from breed groups originally bred for hunting were most protected."2
Interestingly, every resident of Sweden has his or her own personal identity number, and every visit to a hospital is entered into a national database that can be accessed by researchers. In addition, dog ownership registration is mandated. Using the databases, the researchers were able to compile the information required to analyze causes of death among dog owners.
"These kind of epidemiological studies look for associations in large populations but do not provide answers on whether and how dogs could protect from cardiovascular disease," said Tove Fall, Ph.D., associate professor at Uppsala University and study co-author.
"We know that dog owners in general have a higher level of physical activity, which could be one explanation to the observed results. Other explanations include an increased well-being and social contacts or effects of the dog on the bacterial microbiome in the owner.
There might also be differences between owners and non-owners already before buying a dog, which could have influenced our results, such as those people choosing to get a dog tending to be more active and of better health. Thanks to the population-based design, our results are generalisable to the Swedish population, and probably also to other European populations with similar culture regarding dog ownership."3
American Heart Association Acknowledges Dog Ownership Is Most Likely Associated With Reduced Risk of Heart Disease
In 2013 the American Heart Association (AHA) issued a scientific statement acknowledging that dog ownership likely has a protective effect that reduces the risk of heart disease.4 According to The New York Times:
"The unusual message was contained in a scientific statement published on Thursday by the American Heart Association, which convened a panel of experts to review years of data on the cardiovascular benefits of owning a pet. The group concluded that owning a dog, in particular, was 'probably associated' with a reduced risk of heart disease."5
According to Dr. Glenn Levine, a professor at the Baylor College of Medicine and head of the committee that wrote the AHA statement, existing research shows that:
- Pet ownership is probably associated with a reduction in heart disease risk factors and increased survival among patients.
- Dog ownership in particular may help reduce cardiovascular risk, because people with dogs may engage in more physical activity (for example, walking their pet)
- Having pets in the family may be associated with lower blood pressure and cholesterol levels, and a lower incidence of obesity
- Pets can have a positive effect on the body's reactions to stress
Dr. Levine and his colleagues emphasize that existing studies do not necessarily prove pet ownership reduces heart disease risk. Rather, the data supports a possible association between the two, especially where the pet is a dog.
Studies Show Dog Parents Also Tend to Have Lower Blood Pressure
In one randomized trial, 30 patients with borderline hypertension either adopted a dog from a shelter, or put off adoption. In follow-ups at two and five months, those who went ahead with the adoption had significantly lower systolic blood pressure than the other group. When all 30 had adopted a dog, the drop in blood pressure was similar for both groups. These study results were presented by K. Allen at the 22nd Annual Scientific Sessions of the Society of Behavioral Medicine; March 24, 2001; Seattle, WA.6
The second study looked at 48 hypertensive stockbrokers who adopted a dog, a cat or no pet. After six months, pet owners in the group demonstrated fewer increases in blood pressure, heart rate and plasma renin activity during periods of mental stress.7
Seniors With Dogs Are Significantly More Active Than Non-Dog Owning Seniors
Another recent study suggests senior citizen dog parents are able to meet internationally recognized exercise goals as established by the World Health Organization (WHO) through the simple act of walking their canine companions.8
A team of U.K. researchers compared two groups of 43 older adults aged 65 to 81. One group consisted of dog owners; members of the other group did not own dogs. All the seniors lived on their own, and members of the two groups were matched by gender, height, weight, health conditions and walking abilities.
The two groups were evaluated on their time spent walking. They wore monitors to track their movements for three one-week periods over the course of a year. The weeks were chosen so the participants' steps could be measured during different seasons and weather conditions. Past research on this topic has relied on self-reporting by participants as to their level of physical activity. The use of activity monitors in this study provided objective data on patterns and intensity of physical activity, as well as periods of sitting.
The researchers discovered the dog-owning group walked an average of 22 minutes more per day than the dog-less group, which was enough to meet both U.S. and international exercise recommendations for substantial health benefits. And the extra exercise the dog walkers received was "marching," not "just dawdling," according to senior study author Dr. Daniel Simon Mills.
WHO recommends at least 150 minutes of moderate to vigorous weekly physical activity. The U.S. Centers for Disease Control and Prevention (CDC) recommends adults get a minimum of 150 minutes a week of moderate-intensity exercise, or 75 minutes of vigorous-intensity aerobic activity a week. The researchers also found that dog owners had fewer continuous periods of sitting down than non-dog owners. Mills, who teaches veterinary behavioral medicine at the University of Lincoln in England, told Reuters Health:
"It's very difficult to find any other intervention that produces this size of effect. It's good evidence that dog ownership amongst the elderly increases physical activity in a meaningful and healthy way."9
Mills feels the study proves that the exercise benefits of dog ownership stem from having dogs, not from the idea that dog owners are more active to begin with.