As good as it feels to get cozy under blankets and sink into your pillow at night, sleep isn’t a luxury. It's a necessity.
In a 2013 animal study, researchers at the University of Rochester’s Medical Center showed that sleep might allow us to clear toxic, metabolic waste from the brain.1 In other words, sleep is an essential part of detoxification and renewal. University of Bristol researchers confirmed in 2016 that the brain uses sleep time for organization too, by sorting important memories in our internal “filing system” for later.2 It should come as no surprise, then, that poor sleep can take its toll — sufferers of sleep apnea have shown significant changes in two important brain chemicals, causing compromised quality of life, while short sleepers are more than four times as likely to catch a cold.3,4
The rest of the body uses blood and lymphatic fluid to cart away toxic waste from cells, but the brain isn’t equipped with this lymphatic plumbing. Instead, the brain relies on cerebrospinal fluid, which flows through the brain and spinal cord. Cerebrospinal fluid and the brain’s immune system make up the glymphatic system. This system filters out waste and harmful metabolites that play a role in disorders that affect the brain, like dementia and Alzheimer’s disease.
Using mice in the original study, researchers at the University of Rochester tracked the flow of fluid between brain cells and through the central nervous system. They found that brain cells contract. They also found that the space between cells increased from 14 percent of brain volume to 23 percent while asleep.
Even mild sleep deprivation has been linked to anxiety and difficulty processing emotions. Support restful sleep by avoiding stimulants after noon and by taking magnesium, found in Body Ecology Ancient Earth Minerals, as a natural sleep aid.
This translates into a 60 percent increase in space between cells. During sleep, cells are bathed in larger amounts of cleansing fluid than during waking hours.
Researchers also injected mice with amyloid protein — the same protein that builds up like plaque in the brain and is associated with Alzheimer’s disease. It turns out that a sleeping brain is more adept at clearing amyloid plaque than a brain that is awake. Sleep quality matters, and sleep position may matter too. A Stony Brook University study conducted just two years later in 2015 found that sleeping on the side, compared to the back or the stomach, could more effectively remove brain waste and may even reduce risk of developing Alzheimer’s and other neurological diseases.5
"The brain only has 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," says Dr. Maiken Nedergaard, co-director of the University of Rochester Medical Center and lead author of the study. "You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can't really do both at the same time."
Interrupted Sleep and Brain Toxicity
When the brain is not able to clear out waste, it accumulates in the brain like dust on a shelf. The problem is that this waste is toxic, and it can instigate mechanisms like inflammation and cell death.
Signs of toxic waste buildup in the brain include:
• Manic highs and lows7
Neuroscientists have also found that even mild sleep deprivation can fire up anxiety and distort the brain’s ability to process emotions.10 But compared to a short-changed night of sleep, interrupted sleep is far worse, according to a 2015 study from Johns Hopkins Medicine. Researchers discovered that waking up several times in the night can affect positive mood more than short sleep that is not interrupted.11
While previous studies have shown a relationship between mental disorders and sleep deprivation, only recently have scientists teased out a causal link between sleep loss and mood disorders, like anxiety. Unfortunately, those who are more anxious also tend to have a low threshold for missed hours of sleep.
The Problem with Blue Light
Within the brain, there is an internal “clock” that regulates the flow of specific hormones. This internal clock receives direct input from the eyes and, in particular, in response to light.
Researchers at Johns Hopkins University suggest that aberrant light — such as the light from television, in a grocery store, or even a nightlight — is enough to generate depression and changes in mood.12 On studies in mice, they found that even with regular sleep cycles and a normal circadian rhythm, aberrant light triggered the production of more stress hormones, as well as signs of depression and difficultly learning.
Still other studies show that blue light is especially problematic. Many electronic devices emit blue light.
These include devices that many of us look at before going to bed and upon waking:
• Computer screens
In the brain, blue light mimics daylight.13 The human body is hardwired to take cues from the environment — for better or worse. In this case, artificial blue light places unnecessary stress on the body’s sleep and wake cycles, never allowing us to have a proper night’s sleep. Of course, this modern-day tech hurdle is one that affects us all. In 2016, University of California, Irvine, researchers linked compulsive Facebook checking to a lack of sleep among busy college students: Sleep deprivation may make us prone to distraction.14 When studying artificial light that same year, University of Oxford researchers found that, while green light can promote sleep, blue light may delay sleep by as much as 16 to 19 minutes.15
5 Suggestions for a Good Night's Sleep
Sleep ensures the regeneration of new tissue and cells. It literally creates the space necessary for healing, helping the body to defend itself against neurodegenerative disease and long-term mood disorders.
A good night’s sleep is essential for a healthy brain.
For your last meal of the day, we suggest combining Body Ecology grain-like seeds (such as millet, quinoa, buckwheat, or amaranth) with non-starchy vegetables and ocean vegetables. Complex carbohydrates, like those found in grain-like seeds, have a calming effect on the body and stimulate the production of soothing neurotransmitters, which can help ease you into slumber.
Ending the day with a meal that contains complex carbohydrates also safeguards against dramatic drops in blood sugar. Low blood sugar during sleep is a surefire way to release regulating stress hormones that wake you up in the middle of the night. In 2016, researchers found a direct link between what you eat and how well you sleep, associating foods low in fiber and high in saturated fat and sugar with disrupted, less restful sleep.16
To make the most out of every night’s rest, we also suggest that you:
- Avoid stimulants after noon, such as coffee, stimulating tea, and chocolate.
- End electronic communication, like email and texting, around sunset.
- Turn off the television at least 2–3 hours before bedtime.
- Unwind from the day with dim incandescent light or candlelight.
- Consider installing bedroom curtains that block out outside light.
It’s clear that uninterrupted sleep is critical when it comes to flushing and resetting your brain, but how much sleep do you really need to bring your mind and body back into balance each day? The latest research from The Norwegian University of Science and Technology (NTNU) spells it out for us using the “Goldilocks” theory: While too much or too little sleep may not be good for you, a moderate and consistent amount of sleep is just right.
Every person is unique and may have their own specific sleep needs, as the Principle of Uniqueness states. Still, NTNU researchers caution that sleeping less than four hours or more than eight hours a night may come with long-term health risks, including an increased risk of death from some types of heart disease.17
What To Remember Most About This Article:
Sleep may feel like a luxury after a busy week balancing work and home life, but it's also a necessity to clear toxic waste from your brain. Sleep supports brain detoxification and renewal. Brain cells contract and are bathed in cleansing fluid as you sleep.
Toxic waste can quickly accumulate in the brain if it isn't flushed out regularly during sleep. Symptoms like migraines, seizures, depression, anxiety, and even autism may be the result of brain toxicity.
In your brain, you'll also find an internal clock that regulates hormones and responds to light. Blue light from electronic devices may be especially problematic since it mimics daylight. This artificial light can throw your sleep cycle out of whack and affect a sound night of rest.
Support your brain health with good sleep habits, like:
- Avoiding stimulants after noon.
- Ending electronic communication at sunset.
- Turning off the TV 2-3 hours before bed.
- Unwinding in the evening by candlelight or with dim incandescent light.
- Installing blackout curtains in the bedroom to block out light.
- Xie, L., Kang, H., Xu, Q., Chen, M. J., Liao, Y., Thiyagarajan, M., ... & Nedergaard, M. (2013). Sleep Drives Metabolite Clearance from the Adult Brain. Science, 342(6156), 373-377.
- Sadowski, JHLP, Jones, MW & Mellor, JR. Sharp-wave ripples orchestrate the induction of synaptic plasticity during reactivation of place cell firing patterns in the hippocampus. Cell Reports, February 2016 DOI: 10.1016/j.celrep.2016.01.061.
- Paul M. Macey, Manoj K. Sarma, Rajakumar Nagarajan, Ravi Aysola, Jerome M. Siegel, Ronald M. Harper, M. Albert Thomas. Obstructive sleep apnea is associated with low GABA and high glutamate in the insular cortex. Journal of Sleep Research, 2016; DOI: 10.1111/jsr.12392.
- Aric A. Prather, Denise Janicki-Deverts, Martica H. Hall, Sheldon Cohen. Behaviorally Assessed Sleep and Susceptibility to the Common Cold. SLEEP, 2015; DOI: 10.5665/sleep.4968.
- Hedok Lee, Lulu Xie, Mei Yu, Hongyi Kang, Tian Feng, Rashid Deane, Jean Logan, Maiken Nedergaard, and Helene Benveniste. The Effect of Body Posture on Brain Glymphatic Transport. Journal of Neuroscience, July 2015 DOI: 10.1523/JNEUROSCI.1625-15.2015.
- Gale, K. (2004). Epilepsy and Seizures: Excitotoxicity or Excitotrophicity? In Excitotoxicity in Neurological Diseases (pp. 137-170). Springer US.
- Rao, J. S., Harry, G. J., Rapoport, S. I., & Kim, H. W. (2009). Increased excitotoxicity and neuroinflammatory markers in postmortem frontal cortex from bipolar disorder patients. Molecular Psychiatry, 15(4), 384-392.
- Weber, M., Webb, C. A., Deldonno, S. R., Kipman, M., Schwab, Z. J., Weiner, M. R., & Killgore, W. D. (2013). Habitual ‘sleep credit’is associated with greater grey matter volume of the medial prefrontal cortex, higher emotional intelligence and better mental health. Journal of Sleep Research.
- Hynd, M. R., Scott, H. L., & Dodd, P. R. (2004). Glutamate-mediated excitotoxicity and neurodegeneration in Alzheimer’s disease. Neurochemistry international, 45(5), 583-595.
- Goldstein, A. N., Greer, S. M., Saletin, J. M., Harvey, A. G., Nitschke, J. B., & Walker, M. P. (2013). Tired and Apprehensive: Anxiety Amplifies the Impact of Sleep Loss on Aversive Brain Anticipation. The Journal of Neuroscience, 33(26), 10607-10615.
- Johns Hopkins Medicine. "Sleep interruptions worse for mood than overall reduced amount of sleep, study finds." ScienceDaily.
- LeGates, T. A., Altimus, C. M., Wang, H., Lee, H. K., Yang, S., Zhao, H., ... & Hattar, S. (2012). Aberrant light directly impairs mood and learning through melanopsin-expressing neurons. Nature, 491(7425), 594-598.
- Lockley, S. W., Brainard, G. C., & Czeisler, C. A. (2003). High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. J Clin Endocrinol Metab, 88(9), 4502-4505.
- "Researchers link compulsive Facebook checking to lack of sleep.” University of California - Irvine.
- Violetta Pilorz, Shu K. E. Tam, Steven Hughes, Carina A. Pothecary, Aarti Jagannath, Mark W. Hankins, David M. Bannerman, Stafford L. Lightman, Vladyslav V. Vyazovskiy, Patrick M. Nolan, Russell G. Foster, Stuart N. Peirson. Melanopsin Regulates Both Sleep-Promoting and Arousal-Promoting Responses to Light. PLOS Biology, 2016; 14 (6): e1002482 DOI: 10.1371/journal.pbio.1002482.
- St-Onge MP, Roberts A, Shechter A, Choudhury AR. Fiber and saturated fat are associated with sleep arousals and slow wave sleep. J Clin Sleep Med, 2016;12(1):19%u201324. DOI: 10.5664/jcsm.5384.
- Linn B. Strand, Min Kuang Tsai, David Gunnell, Imre Janszky, Chi Pang Wen, Shu-Sen Chang. Self-reported sleep duration and coronary heart disease mortality: A large cohort study of 400,000 Taiwanese adults. International Journal of Cardiology, 2016; 207: 246 DOI: 10.1016/j.ijcard.2016.01.044.
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