Scientists discover the first real reason we need sleep.
We know we need to sleep. We know our brains and bodies work better after sleep. But what we didn’t know, until now, was why.
Scientists have just reported the first major mechanical reason our brains need to sleep — certain cleaning mechanisms in the brain work better when we shut the brain down.
Just like how dump trucks take to the city streets during the pre-dawn hours because there’s less traffic, our brain’s cleaners also work best when there’s less going on.
“This study shows that the brain has different functional states when asleep and when awake,” study researcher Maiken Nedergaard, of the University of Rochester said.
“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.”
We’ve known that our brains consolidate memories during sleep and perform other important functions.
There are also benefits to the body during sleep — resting allows our muscles, bones, and organs to repair themselves.
It also keeps our immune system healthy.
We know that sleep has all of these benefits, but until now we didn’t know any of the specific changes that bring about these sleep benefits.
Charles Czeisler, a sleep researcher at Harvard Medical School in Boston, told Science Magazine’s Emily Underwood that this is the “ﬁrst direct experimental evidence at the molecular level” for why we need to sleep.
The paper was published in the journal Science on Oct. 17.
All of our cells accumulate waste while they are working, and these waste products can be toxic. If they aren’t removed they can build up and kill our cells. Throughout the rest of the body the lymphatic system washes these waste products away, but the brain is cut off from these actions because of the blood-brain barrier.
When the brain is sleeping, channels between cells grow. This allows cerebrospinal fluid into the depths of the brain tissues to flush out toxic proteins that build up during the day, including the kind that are responsible for neurodegenerative diseases like Alzheimer’s.
- Sleep loss can hurt brain like a blow to head (express.co.uk)
- How Sleep Clears the Brain (nih.gov)
- Good night’s sleep may be critical for brain health: Swedish study (ctvnews.ca)
- 5 Big Discoveries About Personal Effectiveness in 2013 (psychologytoday.com)
- Sleep to protect your brain (eurekalert.org)