Restorative Sleep Rejuvenates Our Brains

Sleep is an essential part of a healthy life, and for good reason. A restful night’s slumber can help us face the day ahead, equipping us with restored energy, increased focus, and a better mood. Did you know restorative sleep is critical to rejuvenating our brains? Neuroscientists recognize that sleeping well and spending adequate time in all stages of sleep, especially the deepest fourth stage, is vital to supporting brain health and function.

During deep sleep, the brain undergoes a little housecleaning, thanks to the glymphatic system, which helps clear the brain’s waste products. ^1–3 Researchers from Boston University used imaging to watch 11 people sleep. They discovered that when the brain emits the slow waves associated with deep sleep, what follows is a pulse of cerebrospinal fluid (the fluid present in the brain and spinal cord) that seems to flush out the toxins that may contribute to brain disease. ⁴It’s the brain’s way of getting rid of the trash!

These are exciting findings because it’s been clear for some time that people with degenerative brain diseases have trouble sleeping. Now, it appears that having difficulty sleeping could contribute to advancing brain diseases and cognitive impairment. ³ Certainly, optimal sleep quality is critical to supporting the glymphatic system and rejuvenating our brain health.

Understanding how sleep works

Sleep happens in different stages, and our sleep quality and time spent in each stage can be impacted by age, medications, brain injuries, and other factors. ⁵ Our circadian rhythm is responsible for regulating the sleep cycle, which occurs in five stages: ^2,5

Stage 1 (Wake): The first stage marks our transition from wakefulness to sleep, essentially the time we start to drift off to sleep. During this stage, active beta brainwaves predominate, but as you become drowsy, relaxing alpha brainwaves increase. You can be easily disturbed by noises and other stimuli during this stage.

Stage 2 (Light sleep): In the second stage, the body becomes more relaxed. This stage of sleep is fairly light but moves you closer to deeper sleep, so if you are planning a power nap, you would want to wake up during this stage of sleep. During light sleep, alpha brainwaves are replaced with low-amplitude mixed-frequency (LAMF) activity.

Stage 3 (Deeper sleep): Deep sleep initiates in stage three when your brain begins to produce slower delta waves. Heart rate and body temperature decrease, and you are much less likely to respond to stimuli or be woken during this time. Your brain has a sudden increase in brainwave activity known as sleep spindles, which are important for learning and memory.

Stage 4 (Deepest non-REM sleep): As you move into stage four, your brain produces even more delta waves, making it much harder to wake up. This is the deepest stage of sleep and the most restorative phase, where your body replenishes energy stores and releases chemicals to support immune function and the repair and growth of muscles and other tissues. Don’t forget that this is the sleep stage involved in “brain cleaning.”

Stage 5 (REM): The final stage, known as REM sleep, occurs about 90 minutes after you first fall asleep and can last up to an hour. This is the most active phase of sleep. You dream during REM sleep, and your heart rate, blood pressure, and breathing all increase. The average adult has 5–6 rounds of REM sleep every night. This stage of sleep is vital for learning and memory as this is when your brain is busiest “filing away,” processing, and consolidating information you have learned during the day.

Restoring sleep

Beyond the benefits to brain health, good quality sleep can also lead to increased productivity and concentration, and a healthy immune system. If sound sleep seems out of reach, it’s time to start making impactful changes that help you have restorative sleep each night.

How can you improve your sleep? Say no to afternoon coffee! Caffeine can disrupt your sleep up to six hours before bedtime, so replace coffee and other caffeine-containing beverages with water, herbal teas, or kombucha. You can also establish relaxing bedtime routines like getting to bed at the same time each night, taking a bath, listening to relaxation music, or journalling.

Feeling hungry before bed? It’s best not to eat close to bedtime, but in case of hunger, say no to junk food. Consume snacks that provide protein to balance blood sugar levels and stabilize appetite during the night. Nutritious choices include Greek yogurt, protein smoothies, and nut butters. Creating a relaxed sleep environment is also key. Keep your bedroom at a cool temperature, remove all electronic devices, reduce possible noise disruptions, and minimize all light sources with the use of blackout blinds.

Finally, consider natural health products that help prepare the mind and body for sleep, and promote deep sleep throughout the night.

• Melatonin helps maintain normal sleep-wake cycles, informing the body when it is time to sleep and when it is time to wake up. Declining melatonin production as we get older can alter this rhythm. Supplemental melatonin can help replenish it to improve sleep quality and duration. ^6-7
• L-theanine is neuroprotective, stimulates the production of alpha brainwaves associated with a relaxed state, and increases brain levels of the neurotransmitters serotonin, dopamine, and gamma-aminobutyric acid (GABA) involved in relaxation and memory. ^8-9 Research has shown L-theanine can help reduce the amount of time it takes to fall asleep, sleep disturbances, and the need for sleep medication by promoting relaxation. ⁸
• The amino acid 5-HTP is a direct precursor to the neurotransmitter serotonin and is used to produce some of the body’s melatonin. Supplementation with 5-HTP improves REM sleep, which has shown positive effects in helping people overcome insomnia. ¹⁰
• Insufficient magnesium levels can reduce melatonin and impact the sleep-wake cycle. ¹¹ Magnesium supplementation can calm the nervous system to promote deep sleep.
• Sleep botanicals such as valerian, hops, and passionflower may also provide benefits. Valerian contains multiple active compounds, including valerenic acid and valerenol, which activate our calming GABA receptors to reduce nervousness. ¹² Hops also promotes sleep by impacting GABA receptor activity ¹³, while passionflower is used for nervousness, hyperactivity, and sleep problems. ¹⁴

Getting restorative sleep might be only one part of your path to achieving health and longevity, but it’s an important one that should be a top priority as we get older.

References 

1. Jessen NA, Munk AS, Lundgaard I, et al. The glymphatic system: A beginner’s guide. Neurochem Res. 2015; 40(12):2583-99.  
2. Eugene AR, Masiak J. The neuroprotective aspects of sleep. MEDtube Sci. 2015; 3(1):35-40.  
3. Hablitz LM, Nedergaard M. The glymphatic system: A novel component of fundamental neurobiology. J Neurosci. 2021; 41(37):7698-711.  
4. Fultz NE, Bonmassar G, Setsompop K, et al. Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep. Science. 2019; 366(6465):628-31.  
5. Patel AK, Reddy V, Shumway KR, et al. Physiology, sleep stages. [Updated 2022 Sep 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526132/ 
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8. Hidese S, Ogawa S, Ota M, et al. Effects of L-theanine administration on stress related symptoms and cognitive function in healthy adults: A randomized controlled trial. Nutrients. 2019; 11(10):2362. 
9. Kim S, Jo K, Hong K, et al. GABA and l-theanine mixture decreases sleep latency and improves NREM sleep. Pharmaceutl Biol. 2019; 57(1):65-73. 
10. Maffei ME. 5-Hydroxytryptophan (5-HTP): Natural occurrence, analysis, biosynthesis, biotechnology, physiology and toxicology. Int J Mol Sci. 2020; 22(1):181. 
11. Durlach J, Pagès N, Bac P, et al. Biorhythms and possible central regulation of magnesium status, phototherapy, darkness therapy and chronopathological forms of magnesium depletion. Magnes Res. 2002; 15(1-2):49-66.  
12. Shinjyo N, Waddell G, Green J. Valerian root in treating sleep problems and associated disorders – A systematic review and meta-analysis. J Evid Based Integr Med. 2020; 25:2515690X20967323. 
13. Benkherouf AY, Eerola K, Soini SL, et al. Humulone modulation of GABAA receptors and its role in hops sleep-promoting activity. Front Neurosci. 2020; 14:594708. 
14. Lee J, Han-Young J, Lee SI, et al. Effects of Passiflora incarnata Linnaeus on polysomnographic sleep parameters in subjects with insomnia disorder: A double-blind randomized placebo-controlled study. Int Clin Psychother. 2020; 35(1):29-35.