Sleep Defrags Your Brain, Empties Trash [Study]

You ever feel like a good night’s sleep clears the waste from your mental space and processes through all the garbage floating around your head?

You’re not half-wrong, a new study shows. Sleep indeed diffuses “waste” from our cognitive processes, “cleaning” your gray matter of ambient BS and actually refreshing your little firing neurons. (Takeaway: take the nap!)

The study isn’t just able to shed light on the crucial functions of sleep — but could also pave the way for understanding other neurological issues, such as Alzheimer’s disease, in a more fundamental way.

Dr. Maiken Nedergaard, co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center, explained of the sleep waste management study that our brains “have a cleaning system that almost stops when we are awake and starts when we sleep.”

She adds that the sleep cleansing effect is “almost like opening and closing a faucet — it’s that dramatic.” Anyone else getting a bit snoozy?

Nedergaard’s sleep study was published yesterday in the journal Science, and she and her colleagues call the sleep waste control process part of “the glymphatic system.” As you slumber, the process pushes away cognitive junk and literally flushes mind-gunking waste back out of your brain cells. Pretty neat, huh?

NBC describes the “two-photon microscopy — a new imaging technology that allows scientists to see deep inside living tissue” used in Nedergaard’s research, quoting the lead researcher on the study as saying:

“This study shows that the brain has different functional states when asleep and when awake… In fact, the restorative nature of sleep appears to be the result of the active clearance of the by-products of neural activity that accumulate during wakefulness.”

She adds:

“The brain has only limited energy at its disposal and it appears that it must choose between two different functional states — awake and aware or asleep and cleaning up… You can think of it like having a house party. You can either entertain guests or clean up the house, but you can’t really do both at the same time.”

The study on sleep’s restorative brain effects could lead to developments on how to make the glymphatic system more efficient in humans, she explained.