Having a dog “may extend life,” having a “single dog” does not Dogs may be the heart’s best friend, and two studies suggest that people who have dogs live longer than those who do not. The possible beneficial effects (thought to be a combination of increased physical activity and social support) appear to be stronger in people who live alone with their pets. One study looked at overall longevity, while the other looked at longevity after a heart attack or stroke. We know that physical activity such as walking can help people recover from a heart attack or stroke, and having a dog can encourage people to be more active by taking their dog for a walk. Social support is also important for health, especially when recovering from illness. Dogs provide companionship and may be a way to meet other dog owners in the neighborhood. However, studies have not proven that dog ownership has a direct effect on health, only that it is associated with a longer life expectancy. The two studies, which originated in Canada and Sweden respectively, were both published in the peer-reviewed journal Circulation:CardiovascularQualityandOutcomes. The studies included 3.8 million people with an average follow-up of 10 years. Dog owners were less likely to die during follow-up than people without dogs: Canadian study: Dog owners were 24% less likely to die from any cause Dog owners were 31% less likely to die from cardiovascular disease The Swedish study had similar results. After an average of four years of follow-up, the study found that: dog owners were 21% less likely to die after a heart attack dog owners were 18% less likely to die after a stroke For people who lived alone with their dogs, the numbers were even more striking. For this group, there was a 33% reduction in the chance of dying after a heart attack and a 27% reduction in the chance of dying after a stroke. Conclusion: Having a dog is good for your physical and mental health, whether it encourages you to get out for a walk or simply provides emotional and social support. However, we should not be distracted by the results of the study. There may be differences between people who own dogs and those who don’t, and this has led to some differences in longevity. Dog owners tend to be younger, more likely to have children at home, and have higher incomes. Dog owners may be less likely to smoke, or more likely to eat a healthy diet. Overall, being physically active and having social support and companionship may help you live a longer, healthier life. Whether this is done through dog ownership or through other means may be less important. One final note: a “single dog” is not a dog, and having a “single dog” is certainly not going to extend your life.