Understanding sleep patterns in healthy adult dogs

A new canine sleep study from researchers at North Carolina State University could serve as a baseline for future research on chronic pain and cognitive dysfunction in dogs—which could lead to improved detection and treatment of these conditions.

The study enrolled 42 healthy adult dogs—21 males and 21 females—ranging in age from two to eight years old. The dogs wore collar-mounted activity monitors for two weeks, and their owners filled out a questionnaire on the dogs’ sleep patterns. After analyzing the data, the researchers found that most dogs have two activity peaks during the day: the first from 8 am to 10 am, followed by a midday lull, and then a longer active period from about 5 pm to 11 pm.

All dogs were more active during weekends than weekdays.

NEWStat reached out to corresponding author Margaret E. Gruen, DVM, MVPH, PhD, DACVB, assistant professor of Behavioral Medicine at North Carolina State University, to find out more.

NEWStat: How is your study different from previous canine sleep studies?

Margaret E. Gruen: Surprisingly, there aren’t many studies on this subject in pet dogs. The pace of research into sleep in dogs has moved very rapidly, including the ability to conduct noninvasive polysomnography with dogs. However, the studies on sleep patterns across the day have been conducted either on laboratory-housed dogs or dogs who are not kept the way we currently keep pet dogs (in our homes and even in our beds). This makes it difficult for us to look, in a sensitive way, at what alterations in the sleep-wake cycle really look like. In addition, we used a relatively new analytic technique that allows the richness of activity-monitor data to be explored across each minute of the day and evaluate when shifts in activity occur.

NEWStat: Did the weight and sex of the dogs have any impact on their activity levels?

MEG: Females were more active than males during the evening peak of activity, with some smaller periods of increased activity overnight. Weight had less effect on activity overall, but lighter dogs were more active during periods of the night, with no real differences during the day.

NEWStat: You write in your paper that the purpose of the study was “to establish baseline sleep-wake cycle and activity patterns” in healthy adult dogs. What can these baseline patterns tell us?

MEG: I think these findings give us a foundation for future work to understand the development of adult-like sleep patterns and begin to better define what’s normal so that we can increase our ability to identify what’s abnormal. One of the main signs of cognitive dysfunction syndrome in aging dogs is alterations in the sleep-wake cycle, but we rely on owner reports and have no real way to identify these early in the progression. As we become more able to define what normal looks like, we hope to be able to identify when these patterns become abnormal, especially as wearable activity monitors for dogs are becoming more readily available and widespread.

NEWStat: How could your findings help veterinarians practice better medicine?

MEG: [Our findings can] help veterinarians identify the types of shifts in sleep-wake patterns that are abnormal, and what owners can be watching for as their pets age. Right now, there’s a gap between when dogs likely begin to show these shifts and when we hear about them (which often isn’t until they are bad enough that they are keeping owners awake at night), and we would like to help close that gap. Our previous study [showed] that dogs with osteoarthritis were less active overnight when taking a nonsteroidal anti-inflammatory, suggesting that they slept better when the pain was controlled. This is a convincing argument for treating chronic osteoarthritis pain. I think people can relate to how important sleep is for health.

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