Med thumb dog and cat in bed full size

Dogs live in about 36 percent of American households. And, of the dog-owning population, almost 65 percent of people consider their canine companions to be part of the family. While experts in the human and animal medical communities tend to discourage sharing beds with furry family members, limited evidence suggests that many pet-owners — perhaps about half — do it anyway. And the truth is, we don't really know much about the way pets-in-bed affects human sleep. But a new study, courtesy of the Mayo Clinic, offers some insight into the way four-legged bedfellows affect their owners' sleep, and vice versa. 

The study involved 40 female, middle-aged pet owners and their dogs. Participating humans all slept with one dog (and no more) in the bedroom, but not necessarily in the bed. Participating dogs, who had to be at least six months old, represented a wide variety of breeds. Researchers collected seven nights of sleep data from both canines and humans by strapping activity-tracking bracelets on their wrists. Human participants also kept sleep diaries in which they recorded information about their bedtimes, use of sleep meds, sleep quality and bed partners, as well as where their dogs dozed. 

Humans got the highest-quality and longest nights of sleep when their dogs slept in their bedrooms, as opposed to in their beds or somewhere else in the house. Dogs slept like babes pups in their owners' beds, no matter where they curled up or how many human bed-partners they had. The data, per the study, "suggest that a single adult dog in the bedroom may not markedly disrupt sleep."  

This is the first study, to the best of researchers' knowledge, to provide objective data about the sleep impact of sharing a bedroom with a dog. In the future, expanded research should include pets other than dogs and owners who drift off alongside multiple pets. But the findings still provide a much-needed glimpse into a very common and poorly understood practice.

As a different group of researchers wrote earlier this year, in a paper lamenting the exclusion of animals from the co-sleeping conversation: "Given that sleep accounts for a large portion of human and animal life, and that interspecies co-sleeping impacts humans, animals, interpersonal relations, and interspecies relations," researchers wrote, "there is an urgent need for researchers to truly contemplate “who’s been sleeping in your bed?”'