The claim is owning a dog good for you? It is always situational with finances and the owner(s), but it seems that it is overall true.
The Power of PetsNIH News in Health (.gov)
https://newsinhealth.nih.gov › 2018/02 › power-pets
According to the NIH, pets in general "has been shown to decrease levels of cortisol (a stress-related hormone) and lower blood pressure. Other studies have found that animals can reduce loneliness, increase feelings of social support, and boost your mood.” Incorporating a relationship with your dog in your life can benefit you mentally and socially, but also physically.
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https://newsnetwork.mayoclinic.org/discussion/your-hearts-best-friend-dog-ownership-associated-with-better-cardiovascular-health/)
According to Mayo Clinic, “Owning a dog also has been linked to better mental health in other studies and less perception of social isolation — both risk factors for heart attacks. Dr. Lopez-Jimenez is a senior investigator of this study.” But also, "In general, people who owned any pet were more likely to report more physical activity, better diet and blood sugar at ideal level," says Andrea Maugeri.
The only caveat to this claim is the amount of effort an owner puts into their dog, having a healthy dog is ideal to both groups and taking care of it along with the other responsibilities can be seen as an obstacle but if the right amount of care and mutual relationship is present I think it can be said that owning a dog is good for you.