Translational Research: Characterization of Sleep in Dogs

Until recently, our understanding of canine sleep was limited. A new study establishes a baseline framework that will enable us to better understand, characterize, and treat sleep disorders in dogs—and even in humans.   It was high time that research turned its attention to this topic. The most recent studies on dog sleep dated back more than twenty years. Not only were they outdated by recent discoveries about sleep in general, but they had also been conducted on a limited number of animals in a highly controlled environment. “These older studies do not provide relevant data on how dogs live—and sleep—in real life,” says Margaret Gruen, assistant professor of behavioral medicine at NC State University. She and her team therefore set out to update these outdated findings and fill the knowledge gap. They monitored 42 healthy adult dogs (21 males and 21 females) aged 2 to 8 years for two weeks. Most dogs had two peaks of activity during a typical day: a shorter one between 8 a.m. and 10 a.m., followed by a quiet period around noon, and then a longer active period between 5 p.m. and 11 p.m. All dogs were more active on weekends than on weekdays. The dogs’ weight or sex may influence these periods of activity. In fact, lighter dogs tend to be more active for a short period just after midnight, while females seem to be more active in the evening than males. And naturally, older dogs appear less active than others during activity peaks, even if they are in good health. This comes as no surprise to the researchers, who note that dogs are generally more energetic in the presence of their owners, who are often away during the day. These findings are consistent with other hypotheses formulated previously, with the difference that this study provides concrete, well-defined, and documented data. Thus, this research establishes a baseline for sleep patterns in healthy adult dogs. Using these standards as a reference, it is then possible to better identify abnormalities and detect sleep disturbances more quickly, so they can be treated. In fact, many canine diseases can cause sleep disorders, just as they do in humans. This is particularly true for certain cognitive impairments or chronic painful conditions. Prior to this study, research focused only on disturbances in the sleep-wake cycle, but no reference standards were available. This gap has now been filled, which will enable the study, detection, and treatment of these diseases—and may even lead to a new approach to understanding behavior, development, and aging in dogs. The new data could also prove valuable in human medicine. Translational research in companion dogs offers an opportunity to study sleep and gain a better understanding of sleep disorders in both animals and humans. As true members of the family, dogs not only share a common environment, routine, and, to a certain extent, a pace of life with their owners, but they also exhibit similarities in terms of sleep architecture and cycles. As a translational model for sleep disturbances in humans, dogs thus allow for the identification of the natural and complex factors underlying sleep disorders, unlike mouse models in which these disorders are artificially induced.