“I hate Mondays.”
Do you ever have trouble sleeping after a bad day at the practice?
It could be dogs have the same problem after a bad day at the dog park.
A new study published online in the journal Proceedings of the Royal Society B: Biological Sciences shows that dogs who have a stressful day sleep badly that night, just like people.
Researchers at the Hungarian Academy of Sciences measured the sleep of sixteen dogs over a three-hour period, including a golden retriever, a sheep dog, and a Jack Russell terrier.
The dogs were divided into two groups. Just before the time they would normally go to sleep, one group was given a positive experience and the other group was given a negative experience.
The positive experience included six minutes of quality time with their owners, like a game of fetch, getting petted, and just generally fussed over.
The negative experience included being leashed to a door and left alone. Then a researcher would enter the room in a threatening manner and stare silently at the dogs for a few minutes (if you’re worried about how far the researchers took things, relax—they did nothing to physically threaten or harm the dogs).
Then the dogs were allowed to fall asleep for three hours.
While the dogs slept, researchers used EEG monitors measure their brainwaves.
Researchers discovered that the stressed-out dogs averaged 20 more minutes of REM sleep than the non-stressed dogs. REM (rapid eye movement) is the active stage of sleep. It’s the stage of sleep when people (and dogs) dream, often vividly, and is frequently accompanied by increased heart rate and sudden, twitching movements.
It’s also when people (and, presumably, dogs) work through problems they may have encountered during the day.
Unfortunately, the more REM sleep humans get, the less deep sleep we get. Which means we spend more time tossing and turning restlessly, and less time recharging.
It turns out, the same thing happens to dogs. Dr. Anna Kis, lead author of the study, said, “It suggests that, just as humans have a bad night’s sleep after a difficult day, dogs may have a similar problem.”
One surprising result: the dogs who had a negative experience fell asleep faster than the dogs who had a positive experience, usually within 10 minutes. The dogs who had a good time took an average of 20 minutes to fall asleep.
That’s a major difference in the stress reactions of dogs and humans. “In humans, stress causes difficulty falling asleep,” Dr. Kis pointed out. “Whereas dogs fall asleep more quickly – we think as a protective measure to remove themselves from the stressful environment.”
Regardless, the study shows that stressed-out dogs, like their stressed-out owners, sleep poorly.
Previous dream studies conducted on rats indicate that when rats dream, they’re likely dreaming about things they did that day, like running a maze—the same areas of their brains light up during REM sleep that lit up while they ran the maze.
Scientists say it’s reasonable to assume that dogs are dreaming during REM sleep, too, since their brains are more complex and show the same electrical impulses.
So be careful what you say to your dog patients today. You’ll both sleep better tonight.
Photo credit: (c) Jared_Sislin_Photography