Dogs and owners often move together at night, new study finds

A PLOS One study published on 7 October found that people and their dogs often became active around the same time at night, yet bed sharing was not linked to significantly worse measured sleep duration or quality in its small sample. Ming Fei Li of the University of Toronto, Lavania Nagendran of the University of Toronto Mississauga and colleagues tracked 25 people and 38 dogs over four weeks, according to a report provided by the Public Library of Science.

The finding matters to owners who perceive a dog’s movement as a sleep disruption. Some participants said their dogs disturbed them, but the report says that perception did not correspond to a significant difference in the sleep measures it describes. The study does not establish that sharing a bed with a dog improves sleep or has no effect for every owner.

What the dog and owner sleep study measured

The researchers used activity monitors worn on people’s wrists and dogs’ collars. They compared nighttime movement over four weeks, looking at whether human and dog activity coincided and which member of a pair tended to move first. The report identifies the article as ‘Who is disrupting whom? Examining the nighttime activity patterns of humans and their dogs,’ published in PLOS One.

Nighttime activity was strongly correlated between people and their dogs. More often, the person began moving before the dog, the report says. That pattern complicates the common assumption that a dog is necessarily the first to disturb a sleeping owner: movement appears to run both ways within these pairs. The authors described human and dog activity as closely coupled and said subjective impressions of sleep may differ from objective measurements.

How earlier research compares

An independently authored study published in Animals in 2020 offers a useful comparison. Christy L Hoffman, Matthew Browne and Bradley P Smith monitored 12 adult women and their dogs for an average of about 10 nights each. Their analysis covered 124 sleep periods and 54,533 one-minute observations, alongside the women’s sleep diaries.

That earlier study found a positive association between dog and human movement during sleep periods. Dog movement was associated with a threefold increase in the likelihood that a still participant would start moving. Its authors found that dogs influenced human movement more than humans influenced dog movement in their sample, a different directional pattern from the one described in the new report.

Yet the women in the 2020 study rarely said their dogs woke them. They recalled dog-related disturbance on 22 of the 124 nights. The finding illustrates why movement and remembered disturbance are separate observations: a person can move alongside a dog without later reporting an awakening. The 2020 authors also cautioned that their monitors could not confirm whether recorded movement meant a participant was awake.

What remains uncertain about sleeping with dogs

Both studies are small, and their designs limit broad claims about owners and dogs generally. The 2020 sample comprised adult women near Buffalo, New York, who had one dog and no human bed partner. The new study’s authors noted its limited sample and absence of a dogless control group. Without that comparison, the new findings cannot establish how these owners’ sleep compares with sleep among people who do not share a bed with a dog.

The new study’s authors called for research involving more dogs of different ages and breeds. The 2020 researchers likewise said further work, including methods able to assess sleep more directly, was needed to learn whether the movements they observed affected sleep quality or health. For now, the evidence supports a narrower conclusion: dogs and owners can move together at night, while movement and perceived disturbance do not necessarily tell the same story about sleep.