Another reason why dogs are indeed man's best friends: researchers from the University of Missouri and Miami University discovered that seniors get health benefits from the bonds they form with their doggy companions.

The study, which was published in the journal The Gerontologist, revealed that dog walking is associated with better health for aging people. Aside from being a source of frequent and longer exercise, it is also associated with a lower body mass index, fewer visits to the doctor, and more opportunities for socialization.

The study's news release stated that the Centers for Disease Control and Prevention (CDC) recommends that all adults should spend at least 150 minutes of moderate physical activity every week. For adults aged 60 years and above, walking is usually the most common form of physical activity -- and dog walking fits perfectly in that equation.

The research used data from the Health and Retirement study from 2012 by the National Institute on Aging and the Social Security Administration. It included information on human-animal relationships as well as their activities and health conditions.

Research from the study showed that seniors who developed better bonds with their dogs and took more strolls with their pets are healthier and have more social interactions with other dog owners.

However, a recent report from the Washington Post still advises some caution. While the correlation between dog walking and better health for seniors is there, it does not necessarily mean that dog walking automatically translates to health benefits.

Hal Herzog, a psychology professor at Western Carolina University who studies human-animal relationships, said in the report that it is also likely that the elderly who are already in good health are the ones with the energy to walk their dogs.

The report also highlighted some downsides. For instance, CDC revealed in 2006 that more than 86,000 people are injured each year in falls linked with dogs and cats. As people get older, the likelihood of injury also increases.

So, you might want to think twice before getting Grandpa a puppy. Either way, even without owning a dog -- which in itself has a burden of responsibility -- he can still go on dog walks with a pup from the neighbor or from shelters.

It might also help to know which kind of dog breed would suit your grandparents best. The PetHelpful website lists give dog breeds that are best for seniors, including the ones that serve as watchdogs and do not shed much, which can lead to a lot of tricky cleaning afterward.