The question: Family dogs often spend the night in their owner's bedroom. Might this affect people's sleep?

In this study, the researchers assessed the sleep habits of 40 healthy adults (average age, 44) who had no sleep disorders and who had a dog older than 6 months (average age, 5 years) that slept in the bedroom.

For seven nights, the human participants wore an activity monitor on their wrist, and the dogs wore a similar device on their collar. People spent an average of 7.9 hours in bed and 6.7 hours asleep.

The dogs, on average, played for a few minutes, were active for an hour and slept for about 6.9 hours. People's sleep efficiency - essentially, the time asleep compared with the total time spent in bed - was, on average, 81 percent, regardless of the size of the dog. (Greater than 80 percent is considered satisfactory.)

Sleep efficiency was worse if the dog was on the bed rather than elsewhere in the room: 80 vs. 83 percent. People also spent less time awake after initially falling asleep if their dog was not on the bed. The dogs' sleep efficiency was not affected by their location.

"A dog's presence in the bedroom may not be disruptive to human sleep, as was previously suspected," the researchers, all affiliated with the Mayo Clinic, reported.

Who may be affected?

Dog owners, especially those who let their pet sleep in their bedroom. An estimated 40 million to 60 million households in the United States have at least one dog.

Caveats

Data came from a small number of participants for a short time. The study did not include people with more than one dog in their bedroom and did not include, for comparison, people who did not sleep with a dog in the bedroom. The findings do not apply to other pets, such as cats.

The research was published in Mayo ­Clinic Proceedings.

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This article was originally published by The Washington Post.