Much evidence has been amassed about the potential health benefits of owning pets. So much so, in fact, that a committee of the American Heart Association recently decided to review the science to see what the collective research shows. Their conclusion, laid out in an article published in May,in the journal Circulation, is this:
Pet ownership, particularly dog ownership, probably is associated with a lower risk of cardiovascular disease, and may be a direct cause of lower risk. Although this may seem obvious to many a dog-walker, Glenn Levine, MD, a cardiologist at Baylor College of Medicine and the Michael E. DeBakey Medical Center in Houston who headed the Heart Association team reviewing the studies, said the evidence is based upon statistical correlations between people who own dogs and people who don’t own dogs – not casual observations.
As Levine noted, people don’t say, “Oh, I own a dog and my blood pressure got better.” Rather, he said in an interview, “You hear anecdotal reports about how people like their pets and (the pets) enhance their quality of life, but people don’t anecdotally report that their cardiovascular health is improved.” In fact, there have been greater than 100 studies looking at this correlation, and many have shown improved cardiovascular health when reviewed by his team of researchers.
One of the most compelling studies cited involved 30 participants with borderline hypertension who were randomly assigned to adopt a dog from a shelter or defer adoption of a dog. Subjects in both groups had similar resting systolic blood pressures at the outset. Two and five months after they acquired dogs, the adoption group showed significantly lower systolic blood pressure readings than the deferred-adoption group. Later, after all study participants had adopted dogs, the blood pressure of the deferred-adoption group also was lower then before adoption.
The study was presented at a meeting of the Society of Behavioral Medicine in 2001. Levine and team advocates that more such randomized studies be done. In most research, associations between improved fitness and pet owning relate to walking dogs. One analysis, for example, found dog owners no less likely to be overweight than owners of other types of pets or people who had no pets. But a different analysis that distinguished between dog walkers and dog owners who didn’t walk their dogs found walkers less likely to be obese than people who didn’t walk their dogs or owned no pets.
But the benefit of pet ownership to one’s heart may relate to more than physical activity. The Heart Association team also reviewed studies examining the effects on lowering stress levels of their owners. In one published randomized study, 48 hypertensive patients in high-stress occupations who wished to reduce their stress agreed to acquire or not acquire a pet as part of the study. While all subjects had similar stress levels at the outset (as measured by their systolic and diastolic blood pressure, heart rate and plasma renin activity), those who adopted a pet showed “significantly diminished” stress markers six months later.
The Heart Association team also noted that while most studies involve dogs or cats, the calming effect has been documented as well with chimpanzees, fish, and even a goat and a snake. These were small, anecdotal reports, but still worth mentioning. They are not suggesting you go out and acquire a dog to help your heart, but they are simply noting that it does not hurt, and could be part of an overall plan to maintain a healthy heart. As Levine was quoted, “We don’t want people randomly adopting a dog, neglecting the dog and sitting on the couch eating potato chips and saying, ‘Oh, I’m healthier now.’ ”
Yet, for those of us who already love dogs and cats, and are aware of the commitment that adopting them means, this is good news. There are not just emotional benefits, but physical ones to having them in our lives. Enjoy them, and try to get out while the weather is good.
Dr. Dawn
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