An exciting new physiological reason why optimizing your sleep can dramatically improves your health

Do you struggle with sleep? Perhaps you have difficulty falling asleep at night, or you wake up throughout the night, and/or you feel chronically exhausted during the day. Or maybe you fall asleep fine and stay asleep, but force yourself to wake up early for certain obligations and therefore lower the total time you sleep per night. No matter the reason, a great amount of Americans find adequate sleep to be elusive. In fact, 40% of American get less than 7 hours of sleep while the recommended number of hours is between 7-9 hours for adults according to the National Sleep Foundation (Jones, 2019).

Why does this matter? While countless studies have shown that getting enough sleep is important for our health, earlier this year the Centers for Disease Control and Prevention announced that insufficient sleep has become a public health problem (Lichtenstein, 2015). According to the National Heart, Lung, and Blood Institute, people with sleep deficiency have a greater risk of many health complications, including heart disease, kidney disease, high blood pressure, diabetes, stroke, and obesity (Lichtenstein, 2015). A cumulation of research raises the concern that if a person is not getting adequate sleep, all other health practices, such as diet and exercise, potentially become irrelevant as sleep optimization may take the gold medal when talking about maximizing health.

While sleep is certainly essential to many known physiological functions, such as hormone regulation and metabolism, an increasing body of research suggests that another one of those essential functions may also include the theory of the glymphatic system (or paravascular clearance pathways), highlighting the critical role of sleep in the clearance of many brain toxins (Lliff et al, 2012).

The glymphatic system is a newly discovered pseudolymphatic system in the brain. The word glymphatic is a combination of the words “glial” and “lymphatic” as the glymphatic system is theorized to work through the utilization of glial cells to help clear the brain of waste in a way similar to the lymphatic system. Glial cells surround neurons and hold them in place, supply nutrients and oxygen to neurons, insulate one neuron from another, and destroy pathogens and remove dead neurons. The lymphatic system is part of the vascular system and an important part of the immune system, composed of a large network of lymphatic vessels that carry a clear fluid called lymph. Put these two systems together and there is the glymphatic system theory. Essentially, the glymphatic system  is suggested to actively transport cerebrospinal fluid (CSF) through brain spaces, pushing CSF into glia cells that line the paravascular space and at night, this space expands and harmful proteins and waste products are transported out of the brain (Rasmussen, 2018). Although a full and concrete understanding of the fluid dynamics has not yet been reached, there is promising research suggesting that sleep is critical for this pathway’s brain toxin clearance mechanisms.  What is a consequence of poor glymphatic function? More than likely brain fog, fatigue and depression to name a few!

During sleep, the extracellular space (the space surrounding all the cells) of the brain expands, promoting toxins to be exchanged from CSF into interstitial fluid (part of the extracellular fluid, fluid between cells, Lliff et al, 2012).For example, the protein amyloid beta, which the build up of  is associated with the development of Alzheimer’s, is transported out of the brain via this pathway in rodents (Lliff et al, 2012), and imaging studies have highlighted similar findings of amyloid beta accumulation during sleep deprivation in humans (Rasmussen, 2018). Furthermore, research suggests that this paravascular system may also be imparied in patients with metabolic syndrome/elevated blood sugar and ultimately may contribute to diabetes-induced dementia (Kim et al, 2018). In addition, decreased CSF pressure and volume are correlated with increasing age in humans, which likely also decreases glymphatic flow (Fleischman et al, 2012; Bothwell et al, 2019). Essentially, the increase in interstitial space during sleep is what permits this pathway to be active, as rodent studies have shown that there is reduced or no flow during wakefulness (Jessen et al, 2015).

Ultimately what this all means is that getting sufficient sleep (both time asleep and quality of sleep) is critical. From longitudinal studies, we can see that increased levels of certain toxins, like BPA, may contribute to sleep disorders like obstructive sleep apnea (Berydoun et al., 2016), while an increase in other toxins such as urinary arsenic, phthalates, and polyfluoroakyl compounds have been correlated with more waking episodes during the night (Erden et al., 2014; Shiue, 2017)). Could this be from an overload to the glymphatic system? At the same time, better self-reported sleep has been correlated with improved health outcomes, significantly for mental health and moderately for physical and cognitive health (Gadie et al., 2017). In addition, research has demonstrated sleep’s role in a huge range of illnesses. For example, the liver plays a significant role in biotransformation, and in patients with non-alcoholic fatty liver disease (NAFLD), sleep disturbances and quality have been found to predict 20% of the variability in liver stiffness, suggesting that at least in a compromised liver, sleep is vital (Marin-Alejandre etal., 2019).

Furthermore, a meta-analysis also found a small but significant increase in the risk of NAFLD in patients with shorter sleep duration (Gadie et al., 2017). When research on sleep’s significance with brain health is considered in conjunction with research on sleep’s significance on whole body toxin clearing, the glymphatic system theory of sleep’s critical role in brain toxin clearing becomes increasingly promising.

For many, understanding sleep’s vital role in human health seems like the easy part, as in reality, physically practicing better sleep hygiene can be very difficult. So, what can you do to optimize your sleep? Below is a list of sleep hacks that will help you get a better not sleep, not only leaving you feeling more rejuvenated and alert throughout your days, but also dramatically affect both your mental and physical long term health.

Sleep Hygiene Hacks:

1. Limit blue light before bed/Wear Blue light blockers!
   • So many people like to watch TV before going to bed (or like scrolling through your phone) — but did you know that you could be affecting the quality of your sleep by doing that?
   • The blue light emitted from TV screens, laptops and even smartphones causes your brain to think that it’s daytime and that can inhibit, or at least suppress, the release of melatonin, your body’s sleep hormone.
   • To combat that, you can wear amber-colored glasses that can reduce blue light-induced melatonin suppression by about 60%! That means a higher likelihood of getting to sleep faster and sleeping more soundly after binging your favorite TV show before bed.
   • Such blue light blockers can easily be found on amazon and are not expensive.
2. Keep your room like a cave:
   • Dark
     • Invest in some black out curtains or a sleep mask.
     • Research shows that even dim light during sleep can affect your cognitive function the next day as light mimics your circadian rhythm’s response to natural sunlight, which elicits a physiological response in the body to wake you up.
   • Cool
     • When you go to sleep, your set point for body temperature – the temperature your brain is trying to achieve – goes down, aiding to induce sleep.
     • If you go to sleep in a cooler room, it is easier for this mild body temperature reduction to occur, and therefore easier for you to sleep.
     • Although it differs per individual, it is suggested to keep the temperature of your room between 65-72 degrees Fahrenheit.
   • Quiet
     • Just like light can wake you up and offset your circadian rhythm, so can sound.
     • Anything that alters your attention elicits cortisol release and inhibits melatonin, making falling and staying asleep more difficult.
3. Go to bed at the same time every night and wake up at the same time.
   • Our bodies rely on routine and timing of those routines. Not only is sleep reliant on timing of hormones released in the body, but so are so many other physiological cues that contribute to sleep quality as well. For example cortisol. Our bodies naturally release cortisol at specific times throughout the day so that it is lowest when we are falling asleep.
   • If you’re throwing such rhythms out of wack by one night going to sleep early, calm and collected, and then the next staying up super late jumping on your bed, your body will have no idea when to send appropriate sleep promoting signals the following night. Getting on a schedule helps create predictability for your body systems.
   • This also applies to the time you wake up in the mornings, keep it the same!
4. Limit large meals/eating before bed
   • When you eat a large meal, your body immediately goes to work processing, breaking down, and digesting.
   • Inevitably, when your body needs to be working hard at anything, it is hard for it to simultaneously relax and be in a sleeping state.
   • Also, a full stomach can contribute to not being able to feel comfortably.
5. Keep the bedroom for sleep only/Night time routines
   • This helps train your mind and body for sleep.
   • It is suggested that making it so your bed is only used for sleep and not working, watching TV, eating, etc., will train your body to know it’s time to sleep the moment you get into bed at night.
   • This also comes into play with night time routines. If you have a nightly ceremony before bed (such as always brushing your teeth and washing your face and then putting on your PJs and then combing your hair), this is train your body to know it’s sleeping time!
6. Exercise regularly
   • This is both mental and physical.
   • Mentally, exercising makes your more tired, want to sleep, and feel like you released all the pent up energy from daily life.
   • Physically, hormones and other chemicals are released during and after exercising that aides in feeling more relaxed and ready to rest at the end of the day.

What happens when these things don’t work?  Maybe we should look at your brain? Brain mapping is a tool that has been around for over 50 years and can map our “Delta” level, which is essentially our sleep brain wave.  Brain waves reflect function of neurons and if this is elevated it may be driving insomnia! Brain mapping is a non-invasive way to dive further into the root causes and neurofeedback can actually train these pathways back into a healthier place.  Better sleep usually follows so if you are lacking that energy, clarity and vigor maybe we should look at that Delta wave and see if this is a barrier to your optimal health.

Functional medicine testing like salivary cortisol can also clue us into whether stress is driving problematic sleep.  These tests can look at the circadian rhythm (meaning it varies throughout the day) and help us determine where someone needs help.

We will dive further into sleep and discuss melatonin, cortisol and how stress play a major impact in our circadian rhythms in a further blog but this is something critical to our ability to get deep sleep!  Stay tuned…….
These are just a few of our favorite sleep hacks, however there are plenty more out there, such as breathing exercises, meditation, neurofeedback, supplements, and more. We would love to hear some of your sleep hacks!

Here at Dr. Autoimmune, we strongly emphasize optimizing sleep and can work with each patient on an individual basis to uncover what might be behind their sleep issues and how to work towards an amazing nights sleep!

Your Boulder/Denver functional medicine doctor,
Ian Hollaman, DC, MSc, IFMCP
References:

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2. Lichtenstein GR. The Importance of Sleep. Gastroenterol Hepatol (N Y). 2015;11(12):790
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11. Shiue I. Urinary arsenic, pesticides, heavy metals, phthalates, polyaromatic hydrocarbons, and polyfluoroalkyl compounds are associated with sleep troubles in adults: USA NHANES, 2005-2006. Environ Sci Pollut Res Int. 2017;24(3):3108-3116. doi:1007/s11356-016-8054-6
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