According to recent research, your brain is awakened by a stress transmitter more than 100 times each night.
You wake up. The alarm clock says 02:56.
“Oh no, it is not time to wake up yet,” you think, fearing that you will need lots of coffee to stay awake the following day.
The majority of individuals feel that a good night’s sleep must be uninterrupted. That is why waking up in the middle of the night when all you want to do is sleep can be incredibly irritating.
According to a new study from the University of Copenhagen, the stress transmitter noradrenaline leads you to wake up often throughout the night. But don’t be concerned. It’s all part of a regular, good night’s sleep, and it may even indicate that you slept well.
“You may think that sleep is a constant state that you are in, and then you wake up. But there is a lot more to sleep than meets the eye. We have learned that noradrenaline causes you to wake up more than 100 times a night. And that is during perfectly normal sleep,” says Assistant Professor Celia Kjærby from the Center for Translational Neuromedicine, who is one of the first authors of the study.
Despite the fact that noradrenaline technically causes the brain to wake up more than 100 times every night, we do not consider this to be waking up.
“Neurologically, you do wake up, because your brain activity during these very brief moments is the same as when you are awake. But the moment is so brief that the sleeper will not notice,” explains Ph.D. Student Mie Andersen, the second first author of the study.
Despite the fact that the researchers analyzed mice, their results are most likely applicable to humans since they focused on fundamental biological mechanisms shared by all mammals.
What is Noradrenaline?
Noradrenaline is a stress hormone and transmitter substance, which i.a. is associated with the body’s fight or flight response. It is related to adrenaline, and levels may increase during stress, but it also helps you stay focused.
The stress transmitter noradrenaline affects the sleep waves
Professor Maiken Nedergaard, who has led the study, sees the new finding as an important piece of the puzzle to understanding what happens in the brain when we sleep.
“We have found the essence for the part of sleep that makes us wake up rested and which enables us to remember what we learned the day before. We have found that the refreshing part of sleep is driven by waves of noradrenaline. The very short awakenings are created by waves of norepinephrine, which are also so important for memory,” says Maiken Nedergaard and adds:
“You could say that the short awakenings reset the brain so that it is ready to store memory when you dive back into sleep.”
We will return to the subject of memory shortly.
