Are you washing your brain each night?

At some point you have probably heard that sleep is important. You have probably even experienced the feeling of consecutive nights of poor sleep.

Not good.

Getting good quality sleep has a bunch of potential benefits, including:

• Helps to regulate blood sugar [1]

• Helps to improve athletic performance [2,3]

• Decreases risk of coronary heart disease, high blood pressure and stroke

• Decreases inflammation [4]

• Helps heart health [5]

• Increases attention span and mood [6, 7]

• Boosts memory and learning [8, 9]

• Helps combat germs and keep your immune system strong [10]

• Muscle/tissue repair

• Reduces risk of injury

• Reduces stress

That is a pretty impressive list and I could stop writing this now and just leave you with that list as a solid list as to why getting better sleep is important.

But.

There is some newer research that is shedding light on other benefits of getting quality sleep on top of the listed items.

Sleep for dummies

The paradox of sleep. We are thought to be still and without movement yet our brain is on fire with activity. It is putting in the work while we are fast asleep.

Cerebrospinal fluid (CSF) is a watery liquid that continually circulates through the brain's ventricles (hollow cavities) and around the surface of the brain and spinal cord. CSF washes out impurities from the brain, transfers nutrients and provides protective cushioning to the brain and spinal cord.

Sleep is crucial for both high-level cognitive processing and also basic maintenance and restoration of physiological function [13].

Sleep is also associated with increased interstitial fluid volume and clearance of metabolic waste products into the CSF [14], and clearance is stronger in sleep with more low-frequency EEG oscillations [15].

Researchers think cerebrospinal fluid may flush toxic waste out, “cleaning” the brain, and studies have shown that garbage clearance is hugely improved during sleep [11].

During sleep, brain cells produce bursts of electrical pulses that cumulate into rhythmic waves – a sign of heightened brain cell function [12].

Slow brain waves are associated with restful, refreshing sleep. These brain waves may help flush waste out of the brain during sleep.

A 2019 study [11], gives insight into what drives CSF flow through the brain, suggesting that the same slow waves that coordinate memory consolidation drive oscillations in blood flow and CSF in the brain.

Washing your brain

One of the reasons that we sleep is to cleanse the brain. Our brain cells orchestrate thoughts, feelings, and body movements, and form dynamic networks essential for memory formation and problem-solving [11].

To perform all of this hard work in the wee hours, our brain cells are going to need some snacks. Think of the brain kind of like my children. As they eat, a trail of crumbs, wrappers, cups, bowls, and silverware can be found.

In the brain, this takes the form of metabolic waste. Cleaning up afterward is a necessary step in, potentially, mitigating certain neurodegenerative diseases.

Brain cells require fuel to perform all of their tasks. The brain gets its nutrients from the nutrients in your diet. As the brain cells consume their nutrients, they leave behind metabolic waste. Vile little creatures.

“It is critical that the brain disposes of metabolic waste that can build up. As this metabolic waste builds up it can contribute to the development of neurodegenerative diseases” [11].

Cleaning up after the brain is no simple task. Cerebrospinal fluid surrounding the brain collects toxic waste as it travels. Upon exiting the brain, the contaminated fluid must move into the lymphatic vessels in the dura mater – the outer tissue layer enveloping the brain underneath the skull.

Brain dura mater and lymphatic vessels

Accumulation in the brain of this metabolic waste can lead to neurodegenerative diseases, including Alzheimer’s and Parkinson’s disease.

Oh yeah, and sleep disturbance is also a feature of many psychiatric disorders, like depression to schizophrenia.

So, there is interesting evidence that quality sleep can also help to remove the junk from our brains that could lead to some nasty neurodegenerative and psychiatric diseases/disorders.

It is also common for sleep to become impaired with age. This can further contribute to the poor clean-up of the brain at night.

All the more reason to focus on getting quality sleep each night.

Where to begin?

The key is to work on creating a repeatable nightly routine that gets your body prepared for bed.

I have written about this before (https://www.ebmfitnesssolutions.com/training-blog/tired-of-not-getting-enough-sleep).

You need to start getting ready to sleep prior to getting into bed.

If you try to wind down and calm your mind once you are in bed trying to sleep, you will always struggle.

This newer research, in addition to the oodles of other reasons, should highlight, even more, the importance of getting consistent, quality sleep.

Now, not everyone is going to get eight hours of sleep each night. Is this going to be an issue or can we still get the benefits in less time?

There are studies that have shown that mice that are genetically wired to sleep less have healthy brains. So, it may not be about just the number of hours you get but the quality of the hours you sleep.

This could mean that having a routine that helps you fall asleep quicker and more efficiently could get you into the state of sleep that allows the brain to clean house.

Until next time,

Dr. Tom

References:

[1] Centers for Disease Control and Prevention. (2020, December 10) Sleep for a good cause. Centers for Disease Control and Prevention.

[2] Halson, S. (2020, May 1). Overtraining syndrome in athletes. In F. G. O’Connor (Ed.).

[3] Watson, A. M. (2017). Sleep and athletic performance. Current Sports Medicine Reports, 16(6), 413–418.

[4] Bishir M, Bhat A, Essa MM, et al. Sleep deprivation and neurological disorders. Biomed Res Int. 2020;2020:5764017. Published 2020 Nov 23.

[5] National Center for Chronic Disease Prevention and Health Promotion, Division for Heart Disease and Stroke Prevention. (2021, January 4). How does sleep affect your heart health? Centers for Disease Control and Prevention.

[6] Cirelli, C. (2022, March 13). Insufficient sleep: Definition, epidemiology, and adverse outcomes. In R. Benca (Ed.).

[7] Blackwelder, A., Hoskins, M., & Huber, L. (2021). Effect of inadequate sleep on frequent mental distress. Preventing Chronic Disease, 18.

[8] Puderbaugh, M. and Emmady, P. D. (2022, February 8). Neuroplasticity. In StatPearls. StatPearls Publishing.

[9] Bollu, P. C. (2019, November 5). Normal sleep, sleep physiology, and sleep deprivation. Medscape.

[10] National Heart, Lung, and Blood Institute. (n.d.). How sleep works.

[11] N. E Fultz, G. Bonmassar, K. Setsompop, R. A. Stickgold, B. R. Rosen, J. R. Polimeni, L. D. Lewis, Sleep-wake imaging ROI time series. Figshare (2019)

[12] Jiang-Xie LF, Drieu A, Bhasiin K, Quintero D, Smirnov I and Kipnis J. Neuronal dynamics orchestrate cerebrospinal fluid perfusion and brain clearance. Nature. Feb. 28, 2024. DOI: 10.1038/s41586-024-07108-6

[13] Nina E. Fultz et al. ,Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep.Science366,628-631(2019).DOI:10.1126/science.aax5440

[14] L. Xie, H. Kang, Q. Xu, M. J. Chen, Y. Liao, M. Thiyagarajan, J. O’Donnell, D. J. Christensen, C. Nicholson, J. J. Iliff, T. Takano, R. Deane, M. Nedergaard, Sleep drives metabolite clearance from the adult brain. Science 342, 373–377 (2013).

[15] L. M. Hablitz, H. S. Vinitsky, Q. Sun, F. F. Stæger, B. Sigurdsson, K. N. Mortensen, T. O. Lilius, M. Nedergaard, Increased glymphatic influx is correlated with high EEG delta power and low heart rate in mice under anesthesia. Sci. Adv. 5, eaav5447 (2019).