Dogs in the Bed Did Not Mean Less Sleep for Their Owners

FOR about four weeks, 25 people in Ontario wore an accelerometer on a wrist while their 38 huskies and malamutes wore matching sensors on nylon collars. Every minute, the devices turned movement into a count. Researchers then lined up each person’s nighttime trace with the dog’s trace and asked a deceptively simple question: when one member of the pair stirred, which one tended to move first?

Among 36 human-dog pairs with usable accelerometry data, 22 showed a detectable lagged association in their nighttime activity. In 10 of those pairs, the human moved first. In four, the dog did. In eight, both movements fell within the same one-minute interval. The pattern points away from the easy assumption that the dog is usually the one starting the disturbance.

The Human Often Moved First

The analysis worked by shifting the human and dog activity streams against each other across a five-minute window. A peak with the human trace leading meant the dog’s movement was most strongly associated with human movement from an earlier minute. A peak in the other direction meant the dog led. Across the nights as a whole, more dog movement also tended to accompany more human movement.

That is evidence of coupling, not a verdict about blame. The sensor on the dog’s collar was not validated to classify physiological sleep and wake states, so the researchers described dog movement as activity and inactivity rather than validated sleep and wake states. They also had no video or noise recording to show what produced a movement spike. A paw twitch during dreaming, a person rolling over, or someone getting out of bed can all register as movement without telling us whether either partner actually woke the other.

The nighttime coordination is not entirely surprising. Dogs have repeatedly been shown to synchronize their behavior with people, even when both are free to move independently. Other work has found dogs matching an owner’s location and activity. Dogs also show sensitivity to recurring patterns in human-generated signals. The new study carries that broader sensitivity into the bedroom, where the available signal is much quieter: mostly small movements against a background of rest.

Bedsharing Did Not Worsen Objective Sleep

The second surprise came from the human sleep measures. Across 777 nights, the researchers found no significant effect of dog bedsharing, other dogs in the household, or a human co-sleeper on total sleep time or sleep efficiency. That differs from an earlier home actigraphy study that found lower human sleep efficiency when a dog slept on the bed rather than elsewhere in the bedroom.

Previous work has also pointed in the opposite direction on who moves first. One actigraphy study of women and their dogs found dog movement influenced human movement more strongly than the reverse. Another small co-sleeping study likewise found dog movement leading human movement. The Ontario data therefore do not settle a long-running pattern so much as complicate it: the direction of nighttime coupling may depend on the people, dogs, sleeping arrangements, and methods used.

Owners’ impressions added another layer. Having multiple dogs was associated with worse self-reported sleep quality, even though the objective measures did not show a corresponding sleep penalty. But that result deserves caution because the subjective-sleep model as a whole did not significantly outperform a model with no predictors. More broadly, a review of bedsharing research found that subjective sleep can look better even when objective measures look worse, a reminder that feeling rested and moving less are not the same outcome.

Lavania Nagendran, one of the study’s authors, put that mismatch in personal terms in the University of Toronto Mississauga release. “I would say my dog disrupts my sleep. But it’s really interesting to know that maybe that’s not actually the case,” she said.

A Movement Spike Is Not an Awakening

The limits are substantial. This was a small southern Ontario sample collected during COVID-19 lockdown measures, and the dogs were all huskies or malamutes. The human group was also heavily weighted toward women. Those choices made the study more controlled in some ways, especially by reducing breed-level variation, but they also narrow how far the result can travel.

The strongest finding is therefore narrower than the press release’s language about humans and dogs affecting one another. These animals and owners often moved in a coordinated way at night, and among pairs with a detectable lagged pattern, human movement came first more often than dog movement. That fits experimental evidence that dogs can synchronize movement with their owners, but it does not show that the first mover caused the second to wake.

To answer the question in the paper’s title, a future study would need to see and hear what the accelerometers could not: finer-grained movement, sound, and the behavior behind each spike. The wrist trace and collar trace can show which line jumps first. They cannot yet tell whether that jump was the moment anybody’s sleep was actually disturbed.

FAQ