Sleep Flushes Toxins From the Brain

By Breanna Draxler | October 18, 2013 12:41 pm

sleep, brainSleep doesn’t just clear your head. Scientists now say it literally flushes out waste and toxins that build up in your brain during the day. And your brain needs this beauty sleep more than you might think.

Neuroscientists peeked into the brains of conscious and unconscious mice using a technique called two-photon microscopy. When the mice drifted off, their brain cells actually shrank, expanding the spaces between them by 60 percent. That’s when cerebral spinal fluid flowed in and cleaned the pipes. As the Guardian explains,

During sleep, cerebral spinal fluid is pumped around the brain, and flushes out waste products like a biological dishwasher. The process helps to remove the molecular detritus that brain cells churn out as part of their natural activity, along with toxic proteins.

Plumbing in the Brain

This process is facilitated by the the glymphatic system, which the same group of researchers identified last year, as the BBC describes,

Their findings build on last year’s discovery of the brain’s own network of plumbing pipes – known as the glymphatic system – which carry waste material out of the brain.

Scientists, who imaged the brains of mice, showed that the glymphatic system became 10-times more active when the mice were asleep.

This plumbing system is specific to the brain, since toxin-flushing in the rest of the body is carried out by the lymphatic system, which can’t get its cleaning powers past the blood-brain barrier. And it’s an energy-intensive process, which is probably why you’ve got to be zonked out for it to work. As described in The Verge,

“You can think of it like having a house party,” says Maiken Nedergaard, the study’s lead author. “You can either entertain the guests or clean up the house, but you can’t do both at once.”

Sleep Matters

Housecleaning, as we all know, is a hassle. It’s time-consuming and exhausting and not always at the top of our daily priority lists. But in the case of the brain, it definitely should be. Putting off sleep and the cleaning that comes with it can have lousy longterm effects, according to the findings published in Science this week. The accumulation of waste products in the brain is thought to lead to Alzheimer’s disease and other forms of dementia. According to NPR,

One of the waste products removed from the brain during sleep is beta amyloid, the substance that forms sticky plaques associated with [Alzheimer’s] disease. That’s probably not a coincidence, Nedergaard says.

“Isn’t it interesting that Alzheimer’s and all other diseases associated with dementia, they are linked to sleep disorders,” she says.

So in addition to keeping you bright-eyed and bushy-tailed, sleep will keep your gray matter in tip-top shape, too.

Image credit: Maltsev Semion / Shutterstock

CATEGORIZED UNDER: Health & Medicine, top posts
  • Buddy199

    Who knew?

  • Michael Syroid

    Where is your book available, Sir?

  • Mike Shefler

    Lather, rinse, repeat.

    • colindenronden


  • Margaret Wesner

    I wonder if Meditation serves some of the similar purposes in detoxing the brain by maintaining an alpha state for regular periods. Margaret Wesner, PsyD

    • Michael Bushe

      I came to this page because a friend turned away from meditation because he read this article and a teacher said meditating can replace sleep. My friend didn’t believe it. As a 30-year meditator who doesn’t use an alarm clock, I can personally say that 30 minutes of meditation a day will cause my body to wake up 15 minutes earlier. I don’t think it’s 1-to-1, and I don’t think the brain is washed in meditation – it’s still too active. But I think it replaces some of the need of sleep.

  • colindenronden

    Some of the dreams that I remember are like watching movies, so I suspect the process of watching movies relaxes your brain in a similar way. Often recollected dreams don’t make sense to the conscious mind, but it is as though you have a Eureka ‘that makes sense’ circuit in your brain that gets repeatedly triggered when you are dreaming so that it doesn’t seem like nonsense at the time.

    • Robert A Berezin, MD

      Brain Washing is cute, I like

      my understanding as to how dreams operate. Consciousness in waking life
      operates as a kind of top down functioning. Organized as an invisible play,
      established in early childhood, informs how we filter and process the world.
      Conflicts that are stirred during the day, which resonate with the warp of our
      play inside then need to be digested to leave us open to take on the next day.
      Consciousness operates on the level of people and feeling. Dreams do the
      digestion work during sleep for whatever is generated during the day as it
      resonates with our inner character. Now
      here’s the thing. In REM sleep, we are in a brain-body trance state. The
      attention of consciousness is withdrawn from reality. Consciousness is no
      longer oriented through the senses or the body. Consciousness recedes from our
      striated muscles, so we are in a state of paralysis. Muscle tone is at its lowest
      ebb. Likewise, it recedes significantly from our senses so that we are not
      oriented by reading reality. The eyes, no longer seeing the outside world, dart
      back and forth— with their Rapid Eye Movements— as we see a dream. If any of
      the senses gets stimulated beyond a certain threshold— a loud noise, a strong
      light, a strong touch, even a strong smell or taste— we shift trance states
      back to waking.

      no longer operative in the theater of reality, now operates in a living theater
      of the brain, doing its sleep work. No longer tied to reality, the curtain is
      lifted on this inner theater. A drama, triggered by the events of the day, is
      now onstage. Untethered to reality, it writes its own play, giving us a window
      into the unadulterated nature of consciousness itself. Inner dramas triggered
      by the day’s conflicts are the stuff of dreams. It is through the enactments of
      the dream story that consciousness does its sleep work.

      dreams are about emotional conflicts, the feeling centers in the brain are
      central in the construction of all aspects of dream creation. Consciousness, in
      dreams, is not just a reductive brain rehash. Dreams are an

      alive, creative
      production of consciousness. Dream enactments

      take place in the living
      moment, as do the productions of waking consciousness. It is also essential to
      realize that the actual work of a dream is enacted in sleep with no reference
      to wakefulness at all. Our dreams are not dreamed to be seen by our waking
      selves. They are not a production to be shown in your local movie theater, on
      HBO, or on YouTube. They are purely intended to be shown on the brain’s
      projection screen in sleep. The brain routinely does its REM sleep work

      remember only a tiny fraction of dreams. In fact, we dream about the same
      stirred conflicts five times over the course of the night. Although remembered
      dreams are, in fact, useful in therapy, and can provide eureka moments for us,
      this is not their purpose or function. The happenstance that we remember a
      dream is an unintended by-product of a trance shift on awakening. If the
      purpose of dreams were for us to acquire information about our waking selves,
      remembering far less than 1 percent of them in some seemingly secret code would
      be woefully inefficient.

      • colindenronden

        I think it was Paul McCartney who felt uncomfortable about his song ‘Yesterday’, because most of it came to him during his sleep. People regard their subconscious as another entity that they can’t take credit for its produce. Sculptors often say that the work was already inside the stone, they just released it. Again not wanting to take credit. However, when I was doing Physics homework many years ago and was stumped on a question, I found that if I went to the bathroom the answer would come. This was because being relaxed allowed me to think better, whereas being under stress was more for activating impulses rather than thoughts. But the most relaxed you can be is when you are dreaming. So feel free to own the products of your dreams, they are part of you. August Kekulé, the guy who discovered the benzene ring, had it appear to him in a dream.

        • Robert A Berezin, MD

          I couldn’t agree more

        • Michael Bushe

          Almost all software developers can report being stumped at the end of the day only to wake up with the answer. I look at it as subconscious processing finding the answer but the mind being too busy to see it, until it is less busy.


    any ideas abt people like me who don’t recall dreams/ dreaming. i cannot recall having dreamed in many months, probably a year

    i fall asleep quickly / easily and sleep soundly without awakening until the morning; i generally awaken at same hour each day

  • Jimi

    Team sleep!


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