Updated: Dec 25, 2022
Meditators attend to conditions that affect their practice, and sleep is one of the most impactful. You can skip to the tips listed below, but understanding the biological mechanisms can help inform your practice.
Each cell in our bodies contains a built in timer, or series of clock genes (PER, BMAL, CLOCK, etc) that regulate cell function. These processes are entrained, or fixed, to light cycles. Each cell has its own circadian rhythm. There are subsidiary clocks in other brain regions and peripheral clocks throughout the body. A number of processes throughout the entire gastrointestinal tract and liver, for example, appear to be under circadian control- such as nutrient uptake, processing, and detoxification (Reinke, 2016). The intestinal microbiome is regulated by circadian rhythms, which can significantly impact immune function and metabolism (Voigt et al, 2016). The heart, too, has its own rhythms which affect output, workload, and energy supply-to-demand ratios (Young, 2006). The brain's ability to clear Amyloid-Beta 42, a protein closely linked to Alzheimer's disease, is tied to the circadian cycle (Clark et al, 2022)
When our rhythms are entrained, or fixed to diurnal cycles of night and day, our cells function optimally. When they are disrupted, our hormonal schedules become dysregulated, our mood suffers, our health is compromised. We increase the risk of cancer, obesity, heart disease, anxiety-disorders and depression, Type II diabetes, and the kind of neurodegeneration typical of dementia and Alzheimer's disease.
Mood and attention are dependent on sleep. Dopamine is a neurotransmitter that influences learning, attention, and motivation. Acetylcholine is a neurotransmitter that amplifies activity of brain circuits associated with focus and attention. Norepinephrine is a neurotransmitter that amplifies activity of brain circuits associated with alertness. After a good night's sleep, it's as if stores of these neurotransmitters were replenished. We wake up feeling alert and motivated. By contrast, when we do not sleep well night after night, we wake up with brain fog and begin to feel unmotivated. Over time, this dampens our mood causing chemical imbalances. Anxiety, depression and lack of sleep are strongly correlated.
No drug is as beneficial as sleep is for health. Neither therapy nor pharmaceuticals will avail us much if our sleep is consistently compromised and our habits and sleep patterns are not addressed or corrected. We can start by examining our habits- especially sleep, diet, and exercise. If they're not on point, begin there.
Meditation improves sleep and a good night's sleep improves meditative concentration. Meditation has been correlated with decreased sleep onset latency (SOL), or "sleep onset insomnia." SOL can decrease total sleep time. Meditation helps reverse this.
A good night's sleep helps with memory and learning. Neuroplasticity, which refers to the brain's capacity to form and reorganize synaptic connections, especially in response to learning or experience, occurs during sleep. Knowledge and memory are consolidated after a good night's sleep. The brain regions also synchronize to create motor memory. Sleep is like the Save function in an application, but sleep is also essential before learning. It primes the brain to absorb new information. There's a 40% decrement in memory consolidation without sleep.
A good night's sleep is usually divided into 4 stages: NREM stage 1, NREM stage 2, NREM stage 3, and REM. The stages follow a specific order. Each has a unique function and role in maintaining overall brain health. Stage 1 [NREM (Non-Rapid Eye movement)]. Stage 1 is the transition between wakefulness and sleep. During stage 1 sleep:
Brain activity slows
Heartbeat, eye movements, and breathing decrease
The body relaxes; muscles may twitch
This brief period of sleep lasts about five to 10 minutes. Interestingly, sleep is not a global state. Neuronal populations in different parts of the brain "sleep" before others. As we fall asleep, the thalamus cycles down before the frontal cortex. The thalamus serves as a switchboard or relay station for motor and sensory information. Sensory information still enters the sense doors- the ears still process sound waves, mechanoreceptors still process touch, the nose still detects odors, but, when the thalamus unplugs, the raw data doesn't get interpreted.
We spend approximately 50% of our total sleep time in NREM stage 2, or light sleep, which lasts for about 20 minutes per cycle.
During stage 2 sleep:
We become less aware of our surroundings
Body temperature drops
Eye movements stop
Breathing and heart rate become more regular
In stage 2, the brain produces bursts of rapid, rhythmic brain wave activity called sleep spindles. They are thought to be a feature of memory consolidation—when your brain gathers, processes, transfers, and filters new memories you acquired the previous day (Andrillon et al., 2011).
In NREM stage 3, the slowest brain waves known as delta waves (1.5-4 Hz) peak. Neurons in the thalamus appear to regulate sleep and wakefulness. This stage is referred to as delta sleep, a period of deep sleep where any noises or activity in the environment fail to register or wake the sleeping person.
During NREM stage 3 sleep:
Muscles are completely relaxed
Blood pressure drops
The body starts its physical repairs.
Toxic proteins cleared
The brain consolidates declarative memories— general knowledge, facts or statistics, personal experiences, and other things learned that day (Feld, Diekelmamnn, 2015).
In REM (Rapid Eye Movement) stage 4, the brain is aroused with mental activity, but voluntary muscles become immobilized which prevents us from acting out our dreams.
REM sleep begins approximately 90 minutes after falling asleep. In stage 4:
The brain lights up with activity
The body is relaxed and immobilized
Breathing is faster and irregular
Eyes move rapidly
Memories are consolidated.
Emotions and emotional memories are processed and stored (Glosemeyer, 2020).
When we are alert and awake, signals travel from the dendrites, or arms, of the cells to the soma, or body, of the cell. At the soma, a spike is generated and a signal runs down the axon and on to other cells. During REM sleep, however, dendrites in the prefrontal cortex show increased activity, but the soma shows decreased activity. This decoupling suggests that the neurons are processing information received, but not sending them on. This is consolidation and allows the brain to respond to environmental cues the following day (Aime et al., 2022).
We cycle through these 4 stages several times during the hours we sleep: from light to deep (usually in the first half of the night), then from light to REM during the second half of the night. The brain also wakes up neurologically more than 100 times a night. Waves of noradrenaline trigger short awakenings (usually not detectable to the conscious mind). "Short-term awakenings are a natural part of sleep phases related to memory," asserts Celia Kjarby, lead author of a study published in Nature. These waves are important for the consolidation of learning and memory (Kjaerby, 2022).
A small molecule called microRNA-137 helps regulate a protein in brain cells called hypocretin (Holm et al., 2022). Hypocretin plays a role in the order of the sleep stages. Researchers suspect that hypocretin plays a role in both insomnia, the inability to fall asleep, and narcolepsy, the ability to stay awake. Insomniacs have too much hypocretin the brain; narcoleptics have too little.
During sleep, the glymphatic system clears out toxins and metabolic waste from the brain. It takes 7 to 8 hours for the glymphatic system to flush out metabolic waste. The glymphatic system is like an irrigation system. In conjunction with lymphatic vessels within the brain, noxious toxins are drained into thin tubes-which allows for the circulation and removal of brain waste fluid. That fluid exits the brain and drains into channels in the outer tissue layer that surrounds it (Mehta et al., 2022). Lifestyle choices such as sleep position, alcohol & caffeine intake, exercise, omega-3 consumption, diet, meditation, intermittent fasting and chronic stress all modulate glymphatic clearance for better or for worse.
Side sleeping improves glymphatic clearance compared to either supine (on the back) or prone (front-lying) positions. Alcohol impairs sleep. Ingesting caffeine late in the day (for most people) affects the quality and quantity of sleep. Pharmacologically, caffeine is an adenosine-receptor antagonist (Nehlig, 2004). Adenosine is a hormone that regulates sleep and sleep induction (Huang, 2011). Caffeine blunts adenosine, which explains why it is harder for most people to fall asleep after ingesting caffeine.
Morning exercise is ideal. Vigorous exercise prior to bed is not. It elevates heart rate and body temperature. A falling body temperature is best for sleep.
Many hormones that regulate hunger and appetite are replenished after a good night's sleep. Sleep upregulates the satiety hormone, leptin, and downregulates the appetite-stimulating hormone, ghrelin. Hunger and appetite increase after a poor night's sleep. Not only do we eat more, we crave the kinds of nutrient-poor, sugary foods that compromise sleep, which leads to more stress on the body and mind which leads to more bingeing which leads to weight gain, increasing our risk of stress and illness which further compromises sleep, mood, and affect. Like this, we can easily fall into a negative feedback loop.
Chronic sleep deprivation can negatively affect immune cells which leads to inflammation and cardiovascular diseases . Losing even an hour and a half of sleep a night potentially increases these risks according to a 2022 study published by researchers at the School of Medicine at Mount Sinai.
Daylight Savings Time (DST) is like a global controlled experiment. During the spring, when we lose an hour of sleep, a 24% increase in heart attacks follows that day. In the autumn, when we get an extra hour of sleep, we see a 21% reduction in heart attacks (Gurm, 2018). We see similar patterns in car accidents and suicide rates. Fatal car accidents, attributed to sleep deprivation and circadian misalignment, spike by 6% after DST (Vetter, 2020). Sleep disruptions during the Spring transition are also associated with a 6.25 percent increase in suicide (Osbourne-Christensen, 2022).
Men who sleep five hours or less per night have smaller testicles than those who sleep seven hours or more. Men who sleep five hours or less per night will have a level of testosterone equal to that of men ten years older. Lack of sleep ages a man by a decade.
Sleep deprivation compromises our immune systems. Natural killer cells (NK) identify pathogens and foreign invaders- such as viruses, bacteria- and destroy them. Reducing sleep to 4 hours is associated with a whopping 70% decrease in NK activity. That is a compromised state of immune deficiency which puts us at risk for acute illnesses like the cold or flu and, over the long term, more serious threats like prostate, bowl, and breast cancer.
The very fabric of our lives- our genes and DNA- begin to unravel when sleep is chronically compromised. One study found that after one week of insufficient sleep (6 hours versus 8 hours), 711 genes were up- or down-regulated (Dijk, 2013). Those genes that were down-regulated or switched off were associated with the immune system. Those genes that were up-regulated or switched on were associated with inflammation, tumors, and cardiovascular disease. "Sleep," asserts sleep researcher Matthew Walker, "is a non-negotiable biological necessity."
Again, this partially explains why, in some cases, therapy and prescription drugs will not help. I was such a case. I had insomnia and struggled with sleep most of my life. It affected my moods and relationships, contributing to the collapse of my marriage. I was tired all of the time. When I got home after work, I had no energy for my wife. No, I didn't want to go apple picking. No, I didn't want to go on a date night. No, I didn't want to have dinner with her friends. She misinterpreted this as rejection. More than anything, my body craved rest. I wanted to stay home and just nap most days. Two jobs, a strained marriage, and three young children at home taxed me even more, the stress worsening my insomnia which further increased my stress. We went to marriage counseling. My detachment and lethargy were symptoms, not root causes, but we talked in circles about disconnection. Frustrated, my wife filed for divorce. Desperate to get to the root of the problem, I requested a sleep study after my aunt told me that sleep apnea ran in the family. Obstructive sleep apnea is a serious sleep disorder in which breathing repeatedly starts and stops. This occurs when the throat muscles relax. Loud snoring, episodes in which you stop breathing during sleep, gasping for air during sleep, a dry mouth, difficulty staying asleep (insomnia), excessive daytime sleepiness (hypersomnia), difficulty paying attention while awake, and irritability were some of the symptoms. My doctor did not think I was a candidate initially. Excessive weight and obesity are the most common causes of obstructive sleep apnea. I was athletic and fit. I pressed him anyway and he ordered a sleep study.
I was diagnosed with sleep apnea. In a sense, I was relieved to know there was one condition at the root of most of my distresses. My wife ignored the diagnosis. The marriage did not end happily, but I walked away with insight. The diagnosis made sense. I could see the exhaustion and the stress and the sadness and irritability that often tormented me within context and in an objective way that appealed to my logical mind. The problem was biological, not moral. It was solvable and reversible, and I was determined to hack my own body and mind to fix this.
With sleep apnea, I control what I can. I sleep well most nights by following the simple protocols listed below. Some tips may be familiar (like sticking to a sleep schedule), and some may be unfamiliar (like sleep tape). What works for me may or may not work for you. Consult with a professional first and experiment for yourself.
Tips on sleep
Exercise daily. 30 minutes of vigorous exercise is best, but even light exercise is better than no activity. Avoid exercising prior to bed as this may stimulate both mind and body. You might consider exercising in the morning. As the sun rises, you may find me running to and from the neighborhood gym. This is intentional. Natural sunlight triggers photosensitive ganglion cells in the retina. This activation primes the superchiasmatic nucleus which sets our circadian clock both globally and at the cellular level.
Use bright light to help manage your circadian rhythms. Avoid bright light in the evening and expose yourself to sunlight in the morning. This will keep your circadian rhythms in harmony with diurnal rhythms.
Avoid caffeine well before bed which can disrupt sleep. As the day progresses, levels of the hormone adenosine gradually increase in areas of the brain that are important for promoting arousal. Elevated concentrations of adenosine inhibit arousal and cause sleepiness. The more adenosine builds up over the course of the day, the sleepier we feel. By the end of the day, I am ready for a good night's sleep. Caffeine blunts adenosine, by binding to the receptor sites. Even though the body is tired, I remain awake long after bedtime if I have a caffeinated drink after 1PM.
Avoid alcohol. Alcohol is a sedative. It blocks REM sleep, which is critical for mental health and recovery. Alcohol also fragments sleep, punctuating it with more awakenings and disturbing the natural cycle.
Eating big or spicy meals can cause discomfort from indigestion that can make it hard to sleep. If you can, avoid eating large meals for two to three hours before bedtime. Try a light snack, like kiwi (which has been shown to improve sleep onset, duration, and efficiency) or tart cherries, 45 minutes before bed if you’re still hungry. I fast intermittently. My last meal of the day is between 2 and 4 PM. This gives the digestive system a rest.
Sugar is a stimulant. I avoid sugary foods. I'm vegetarian. My last meal consists of foods high in tryptophan, a precursor to serotonin, the calming molecule. Kiwi, tart cherry, pumpkin seeds, chocolate, banana, peanuts, oats, bread, and cheese are some foods high in tryptophan.
Sauna. Sauna bathing is associated with many health benefits, from cardiovascular and cognitive health to physical fitness and muscle maintenance (Patrick, 2021). But there's one more benefit: improved sleep. Heat improves circulation, bringing in essential nutrients for repair, and clearing out waste. Heat reduces muscle soreness, helping us relax before bed. Heat increase sbody temperature. But how does an elevated body temperature promote good sleep? Heat increases body temperature which stimulates sweating which cools the body, signaling that it’s time for sleep. Our circadian cycle is controlled by light and the rise and fall of bodily temperature over the day. Sweating isn’t just for cooling off. Studies show that sweating helps eliminate dangerous heavy metals like lead, mercury, arsenic and cadmium from the body. This process, called detoxification, is energy intensive and can cause you to feel sleepy, heavy, and ready for a long sleep. Saunas promotes relaxation of mind, and a relaxed, untroubled mind unwinds with ease and stays asleep.
Hydration is important to our overall health. I drink half my body weight in fluid ounces each day, but stop after about 2PM, as frequent midnight bathroom runs would undermine the health outcomes I'm trying to achieve.
Stick to a sleep schedule- even on the weekends. This helps to regulate your body's clock and helps you fall asleep and stay asleep for the night. If possible, follow Nature's rhythms- wake up before the sun rises and go to bed after the sun sets.
Practice a relaxing bedtime ritual. My rituals include a gratitude practice, microjournaling as a form of brain dumping, and an autopsy performed on the day that has just passed. I reaffirm my intentions for the following day and visualize simulations in my mind.
Wind down. Your body needs time to shift into sleep mode. I meditate myself to sleep. Or try reading the research on sleep; it'll put you to sleep.
Deep, diaphragmatic breathing with slight breath holds. Because of sleep apnea, my oxygen levels fall at night. Deep breathing techniques help improve oxygen efficiency. Breathing also modulates a wide range of cognitive functions such as perception, attention, and thought structure. During sleep, breathing acts as a pacemaker that entrains the various brain regions and synchronizes them with each other. Respiration coordinates neuronal activity in the hippocampus, medial prefrontal and visual cortex, thalamus, amygdala, and nucleus accumbens by modulating the excitability of these circuits (Karalis, 2022). This coordination is essential for memory consolidation.
Sleep tape. After reading James Nestor's Breath, I began taping my mouth closed to force nasal breathing. I used a small strip of painter's tape. Within a few weeks, I began to notice a difference in the quality of my sleep. I found this more effective than the CPAP machine- which I eventually discarded. I began sleeping through the night and felt more rested. Interestingly, there were fewer, if any, midnight bathroom runs. This can be dangerous, so, again, consult an expert.
Avoid electronics before bed or in the middle of the night. Using an electronic device such as a laptop can make it hard to fall asleep, because the particular type of light emanating from screens stimulates the brain. It is best to take work materials, computers and televisions out of the sleeping environment.
Sleeping pills do not produce naturalistic sleep. Most sleeping pills are classed as sedative hypnotics. Sedation does not give you the restorative natural benefits of sleep. Supplementation may be better.
I found Magnesium L-Threonate (300-400mg), Apigenin (50-100mg), and L-Theanine (100-200mg), and 900mg of myo-inositol effective supplements to help me stay asleep. It took less than a week to notice the effects. I do not recommend melatonin or 5-HTP. These will help you fall asleep faster, but you may find yourself waking up in the early morning feeling quite alert and unable to return to sleep. I only use melatonin for jet lag- and only for a 1-3 days. I also supplement with Omega 3 krill oil prior to bed which improve glymphatic functioning (Ren et al, 2017).
You may also benefit from recording your sleep in a sleep diary to help you better evaluate common patterns or issues you may see with your sleep or sleeping habits. I use an Oura ring and a Fitbit Charge 4 to track my sleep. The data is not as reliable as what one would get from lab-grade equipment, but these wearables are accurate enough and affordable. The data is granular. Sleep is divided into 90 minute ultradian cycles. It shows how long I'm in REM sleep, deep sleep, light sleep and awake. The range for men my age is 15-25% (REM), 12-18% (Deep), 40-60% (Light), and 10-20% (Awake). The higher the percentage of REM and deep sleep, the better the quality. So, I can examine the results and experiment. My average sleep score was 85/100, but has been improving steadily as I continue experimenting and making minor modifications. Several times a week, they are in the 90s. I use the tips I suggested above to obtain these results.
I use an oral appliance to correct mild airway obstruction due to sleep apnea.
Evaluate your room. Design your sleep environment to establish the conditions you need for sleep. Keep your bedroom cool (between 60 and 67 degrees) and free from noise or light. I use blackout curtains, eye shades, ear plugs, and a "white noise" app.
Sleep on a comfortable, supportive mattress. Quality mattresses have a "life expectancy" of about 9 or 10 years.
Some people have biphasic sleep patterns. Biphasic sleep describes a pattern of sleep that is divided into 2 phases. This happens to me occasionally. I may sleep from 8 to 2, then 4 to 6. When this happens, I usually meditate myself back to sleep.
If you’re still having trouble sleeping, speak with your doctor or find a sleep professional. I requested a sleep study. Consult with an expert. I can not stress the importance of this enough.
Knowledge is worthless if it is not applied. So, I encourage you to test these protocols and see for yourself. Save yourself time by consulting an expert. May you find what works best for you.
Originally published 4/25/2020.Updated and republished 6/1/2022