STUDY: Dogs could lengthen your life span

(CBS) -- Dogs do so much for their human companions, and new research suggested that dogs may actually prolong a single person's life span.

The study published in the journal Scientific Reports surveyed more than 3.4 million Swedes, middle-aged and older, for a period of 12 years. At the beginning of the study, all those surveyed were free of heart disease.

Individuals living alone with a dog were 11 percent less likely to die of heart disease, according to the study, and a third less likely to die from any other cause compared to people living alone with no dog.

Though the research cannot prove cause-and-effect, the lead researcher of the study reported that there are many reasons having a dog will positively affect owners.

"We know that dog owners in general have a higher level of physical activity, which could be one explanation to the observed results," said Tove Fall, an associate professor in epidemiology at Uppsala University in Sweden.

Experts in the United States agreed that the research is sound.

"Stress relief through companionship has an inherent benefit to people's overall health, so it is not surprising that dog owners display a lower risk of heart disease," said Dr. Satjit Bhusri, a cardiologist at Lenox Hill Hospital in New York City.

Dr. Gisele Wolf-Klein, director of geriatric care at Northwell Health in New York, said that dogs can motivate their owners to remain active.

"The responsibilities associated with dog ownership impose mandatory daily exercise -- a schedule which cannot be impacted by adverse weather conditions, personal commitments or mood swings," Wolf-Klein said.

Mwenya Mubanga, junior author of the study and graduate student at Uppsala, suggested that may be especially important for single people.

"Perhaps a dog may stand in as an important family member in the single households," Mubanga said in the news release.

Wolf-Klein said, "The findings of the largest ever investigation of the association between dog-ownership and human health should encourage all of us to add a four-legged friend in our family circle."

In any case, if you don't already have one, it may be time to start thinking about shopping for a new dog.

You can look at adoptable dogs, as well as cats and other animals, online on the Young-Williams Animal Center's website and the Humane Society of the Tennessee Valley.