25 Humans, 38 Dogs: Toronto Study Finds Pets Don't Disrupt Sleep

A study published Wednesday in the journal PLOS One found that people who sleep in the same bed or room as their dogs do not experience measurably disrupted sleep, and that humans are more likely to disturb their dogs' rest than the reverse, NBC News reported.

The research was led by a team at the University of Toronto and conducted during the Covid-19 pandemic as part of a larger project comparing the activity patterns of socialized wolves and domestic dogs, according to the outlet.

How did researchers measure dog and human sleep?

The study tracked 25 human volunteers and their 38 dogs in southern Ontario over four weeks using wearable activity trackers similar to Fitbits, NBC News reported. The humans wore the devices on their wrists; the dogs — all huskies and malamutes with no reported health problems — wore them on their collars.

Most of the dogs slept on the bed or in the same room as their owners, though a few slept in separate rooms, said study author Lavania Nagendran, an anthropology researcher, according to NBC News. Researchers used the tracker data to analyze what Nagendran called "objective sleep measures," including sleep duration and sleep quality for both species. Human volunteers also filled out a survey self-reporting how well they thought they had slept.

Did dogs actually disrupt people's sleep?

According to the tracker data, no. NBC News reported that sharing a bed with dogs did not affect how well or how long either the humans or the dogs slept, based on the objective measurements.

There was a gap between perception and data, however. Half of the human participants — particularly those sleeping with more than one dog — reported interrupted sleep on the self-report survey, even though the tracker readings did not show that disruption. "When we looked at the subjective, or people's perceived, sleep, we saw that there were people who reported poor sleep if they had multiple dogs," Nagendran said, according to NBC News. "But, again, that wasn't seen" in the objective tracker data.

So who is disturbing whom?

The tracker data pointed the other way. Humans and dogs tended to become active at roughly the same times during the night, but it was the humans who moved first, according to NBC News — meaning people were more likely to disturb their dogs' sleep than dogs were to disturb theirs.

Study co-author Ming Fei Li, who was a graduate student in evolutionary anthropology during the research, told NBC News the sense of safety people report while sleeping near their dogs may point to "a deeper evolutionary history" between the two species.

"A deeper evolutionary history" — Ming Fei Li, study co-author, on why humans report feeling safer sleeping near dogs.

What are the limits of the study?

The sample was small and narrow: 25 people and 38 dogs, all huskies and malamutes, in one region of Ontario, tracked for four weeks. NBC News did not report whether the findings would extend to other breeds, climates, or living arrangements, and the study's origin as part of a wolf-versus-dog activity comparison means the dog sample was not chosen to represent typical household pets broadly. The mismatch between self-reported sleep quality and tracker-measured sleep quality is itself a finding that researchers may need to explain in further work, since it suggests perception of poor sleep near multiple dogs does not necessarily reflect measurable sleep loss.

What should pet owners watch for next?

• Whether follow-up studies replicate the finding across other dog breeds and larger, more diverse samples.
• Further research into why self-reported sleep quality diverged from tracker data, especially among owners with multiple dogs.
• Additional work on the "evolutionary history" explanation Li offered for why humans report feeling safer sleeping near dogs.
• Peer commentary on the study, published in PLOS One, as other sleep researchers respond to the tracker-based methodology.

The original study and its full methodology are described in the NBC News report, which cites the PLOS One publication and interviews with study authors Lavania Nagendran and Ming Fei Li.