The importance of being a sleeping beauty

How many of us have found ourselves cramming for an exam the night before we take it? Hunching over the textbook and attempting to memorize one more chapter through weary, bloodshot eyes, we push ourselves to “pull an all-nighter.” We believe that this practice will ensure our success during the exam, but in reality, it is lessening our chances. Why? Because we must remember that, as humans, we require an adequate amount of sleep in order for our brain to function properly throughout the day. In other words, humans are a bunch of sleeping beauties! 

How exactly does sleep support the brain? To answer this question, let us begin by understanding the exact pathway that is most impacted by sleep! 

The Glymphatic System 

The central nervous system possesses a network of vessels that are responsible for filtering and eliminating metabolic waste products* found within the cerebrospinal fluid*, and this network is referred to as the glymphatic system (Jessen, 2015). This vascular network not only removes metabolites from the central nervous system, but it also supplies the brain with glucose (sugars), lipids, and important modulators that aid in its productivity (Iliff, 2013). Part of the glymphatic system is constantly filtering toxins from the brain, but during wakefulness, this system is less active (Jessen, 2015). During sleep, however, levels of norepinephrine* decline, which expands the extracellular space* of the brain and decreases resistance to the flow of cerebrospinal fluid. Now that there is greater movement of cerebrospinal fluid, there is a greater rate of metabolic waste product clearance (Plog, 2018; Reddy, 2020). Therefore, when we make the decision to “pull an all-nighter” rather than go to bed, there are more toxins in the brain that cannot be removed. What is the result of having these toxins in our brain for too long?

Consequences of Sleep Deprivation 

Whenever our bodies do not rest for extended periods of time (i.e. more than 24 hours), then we become sleep-deprived, and our bodies respond accordingly. According to The Sleep Foundation, some of the most common symptoms of sleep deprivation include (Suni, 2021): 

★ Slow thinking and processing 

★ Reduced attention span 

★ Worse memory 

★ Poor decision making 

★ Lack of energy 

If sleep deprivation continues over a long period of time, then our brains experience dangerous, permanent changes that increase the likelihood of developing physical, neurological, and psychological illnesses, such as (Suni, 2021): 

★ Diabetes 

★ High Blood Pressure 

★ Alzheimer’s Disease 

★ Depression 

★ Bipolar Disorder 

★ Anxiety 

As you can see, it is very important to make sure that we get enough sleep every night in order to protect our brains - and our bodies - from diseases. So close that textbook, walk into your bedroom, and go to bed because you are a sleeping beauty!

*Important Definitions 

Metabolic waste products: substances that are left over from bodily processes that cannot be used by the organism and must be removed. This includes nitrogen compounds, water, carbon dioxide, phosphates, sulfates, etc. 

Cerebrospinal fluid: a clear, colorless liquid found in your brain and spinal cord that helps with muscle movement, organ function, etc. 

Norepinephrine: a naturally occurring chemical in the body that acts as both a stress hormone and neurotransmitter (a substance that sends signals between nerve cells). 

Extracellular space: the space outside of and between cells (e.g., neurons) that contains various substances (e.g., proteins, hormones, ions) that have the ability to affect cellular function.

Citations 

Iliff, Jeffrey J., et al. "Brain-wide pathway for waste clearance captured by contrast-enhanced MRI." The Journal of clinical investigation 123.3 (2013): 1299-1309. 

Jessen, Nadia Aalling, et al. "The glymphatic system: a beginner’s guide." Neurochemical research 40.12 (2015): 2583-2599. 

Plog, Benjamin A., and Maiken Nedergaard. "The glymphatic system in central nervous system health and disease: past, present, and future." Annual Review of Pathology: Mechanisms of Disease 13 (2018): 379-394. 

Reddy, Oliver Cameron, and Ysbrand D. van der Werf. "The sleeping brain: harnessing the power of the glymphatic system through lifestyle choices." Brain Sciences 10.11 (2020): 868. 

Suni E, Dimitriu A. Sleep Deprivation: What it is, its causes, symptoms, and long-term effects on physical, mental, and emotional health. Sleep Foundation. June 2021. 

https://www.sleepfoundation.org/sleep-deprivation. Accessed March 4, 2022.