Turns out your dog doesn't have to perform any Lassie-like heroics to save your life. Just having your favorite furball laying around the house doing nothing but demanding treats reduces your risk of dying by an impressive 24 percent, according to a new review of ten studies that examined data on 3.8 million people. 

Having a dog does your heart good (literally). 

The new research, published in the journal Circulation, offers happy news for dog lovers.

"Dog ownership was associated with a 24 percent risk reduction for all-cause mortality as compared to non-ownership," declare the authors. 

Owning a dog was even more protective for those suffering from cardiovascular illness. Your chance of dying after a heart attack, for instance, drops 65 percent if you own a dog. The chance of dying after a stroke is 27 percent less for dog owners. 

Why does owning a dog have such a protective effect on your health? The first and most obvious explanation is that your pet pooch probably requires walking and playing. And even a little more movement can keep your heart healthy or help it recover after an illness. 

"Several studies have shown that acquiring a dog perforce increases physical exercise (as anyone who has unsuccessfully tried to sleep past the time of a dog's routine morning walk can attest)," writes Dr. Dhruv S. Kazi in an editorial accompanying the findings. Research shows that a surprisingly small amount of extra walking can have big impacts on health outcomes, so this part of the explanation isn't a huge shock. 

Other aspects of the link between dog ownership and health are less expected. For instance, when you walk your dog, for obvious hygiene reasons, you do it outside. And being outside, Kazi notes, has also been linked to big health benefits. The human body just seems to work a little better when it's out in nature.  

Finally, as any pet owner can tell you, dogs help keep loneliness at bay and loneliness, science has shown, can actually harm your health as much as smoking 15 cigarettes a day (yes, that's from a real fact from a reputable study). 

"Dogs offer companionship, reduce anxiety and loneliness, increase self-esteem, and improve overall mood," Kazi stresses. That improvement in mental health translates to less stress-related wear and tear on your body and heart. 

So if you have heart trouble you should definitely think about getting a dog, but don't wait for grim news from your cardiologist to consider pet ownership. 

"The overall understanding of cardiovascular health is that the earlier that we implement healthier behaviors, the better. So like walking, not smoking. And I think that maybe dog ownership is part of that," lead author Caroline Kramer told CNN

More joy and more days

While this sort of observational study can't definitively prove that owning a dog causes all these benefits (for that you'd need to randomly assign dogs to one group and measure the effects against a control group), the evidence that your furry couch potato is helping you live longer is clearly piling up. 

But that's just a sweetener for dog lovers. 

They already know that their beloved pooch makes every day more joyful. This study has just shown that on top of all the love, your dog is probably giving you a bit more life too.