Scientists have long tried to unravel the mystery of sleep. What is happening to our brains and bodies while we snooze? Why is sleep so important that we spend (on average) more than 25 years of our lives doing it? The more research that is done around sleep, the more we realize that there is no single right answer.
Current Theories Behind Sleep
We know that sleep is crucial. Our bodies and brains get rested overnight, allowing them to repair in the process. We also form long-lasting memories while we sleep. Getting into rapid eye movement (REM) sleep is important in moving short-term memories into long-term memory.
Conversely, sleep also plays a role in getting rid of unimportant memories. That's why you probably can't remember what you had for dinner five nights ago. Your brain didn't need that information, so it cleared it out of your system while you were fast asleep.
A New Theory: Bath Time for Your Brain
Recent scientific research shows yet another reason why we may need sleep — to clean our brains. The area inside our skulls is composed of three things: brain, blood, and cerebrospinal fluid (or CSF).
CSF is a clear fluid that resembles water and travels throughout the brain and spinal cord. It runs deep into the brain by coursing along the vessels that supply blood to every part of the brain.
You may ask what this has to do with sleep? Let's dive in.
The Connection between CSF and Sleep
Neurosurgeons for the University of Rochester examined these fluid channels during sleep in the brains of mice. While the mice were sleeping, the researchers were surprised to find that the amount of CSF increased by 60%. A rush of fluid swept through the brain during sleep. It's as if sleep opened a faucet to let more fluid wash the brain.
What role could such fluid play? It turns out that this fluid was essentially scrubbing the mouse brains clean during sleep. Toxic proteins that built up during the waking hours were rapidly removed thanks to this increased flow.
One particularly toxic protein, known as beta-amyloid, was studied closely. And sure enough, beta-amyloid was getting removed from the brain during sleep.
Beta-amyloid and the Brain
What exactly is beta-amyloid? It's a protein that is found in the brains of people that suffer from Alzheimer's disease. Since sleep helps with its removal, it leads to the question of whether getting restful, adequate sleep may help prevent Alzheimer's.
On the other hand, could sleep deprivation make it more likely for humans to develop Alzheimer's in older age? Research is ongoing to find a link.
So the next time you're deciding whether to skimp on the shuteye, just remember the many reasons your brain needs to sleep. Rest well and you'll wake up with a happy, energetic, and clean brain.
