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The Science & Practice Of Perfecting Your Sleep

Key Takeaways

  • “Sleep is probably the single most effective thing you can do to reset your body and health” – Dr. Matthew Walker

  • Sleep is so significant in our health, you really can’t sacrifice non-REM deep sleep or REM sleep without damage

  • “There is no major psychiatric disorder we can find in which sleep is normal.” – Dr. Matthew Walker

  • REM sleep is the most predictive of longevity and lifespan

  • Any amount of alcohol and THC will disrupt REM sleep

  • If you can nap without disruption to your sleep at night – go for it! Otherwise, stay away from naps

  • Pro-sleep behaviors: sleep and wake up at regular times, keep the temperature cool, keep the room dark, limit caffeine intake window, do your best to minimize or eliminate alcohol, have a wind-down routine

  • Priority of events to improve sleep: behavioral tools (light viewing behavior, caffeine, and alcohol, etc.) – nutrition – supplementation – prescription drugs – brain-machine interface

  • Unconventional tips for better sleep:

  • Don’t alter your sleep schedule if you have a bad night of sleep

  • Have a wind-down routine

  • Write down your worries from the day 1-2 hours before sleep

  • Remove all clocks from your room and don’t check the time on your phone

Sleep Cycles And Nuances Of REM Sleep

  • Sleep is the most fundamental layer of physical and mental health

  • “Sleep is probably the single most effective thing you can do to reset your body and health” – Dr. Matthew Walker

  • Sleep as a process is complex in terms of physiology

  • Our assumption has been that we evolved to sleep but it’s possible that from sleep, wakefulness emerged

  • Sleep is separated into two main types: (1) rapid eye movement (REM) sleep and (2) non-REM deep sleep

  • Sleep cycles: non-REM and REM play for brain domination throughout the night in 90-minute cycles

  • The ratio of non-REM and REM throughout the night: the first half of the night is dominated by non-REM deep sleep; the second half of our sleep is dominated by REM sleep

  • If you sleep hours later than usual (maybe because of an event) – you will likely have more REM sleep cycles and less deep sleep

  • REM sleep is often called “paradoxical sleep” because the brain is highly active in this stage

  • We also see serotonin and norepinephrine shut off during REM sleep, and acetylcholine ramp up

  • In REM sleep the brain paralyzes the body so the mind can dream safely without body taking action

  • Just before entering REM sleep, the brainstem sends a signal down the spinal cord and locks the voluntary muscles of the body in paralysis

  • Only two voluntary muscle groups are not paralyzed: (1) extraocular muscles and (2) inner ear muscle – though the reason these two are spared is unknown

  • REM sleep is nature’s emotional regulation and therapy

  • Studies have shown an inverse relationship between REM sleep and all-cause mortality: the lower your REM sleep, the higher all-cause mortality

Non-REM Deep Sleep & Stages Of Sleep

  • There is really no state in wakefulness that is like true slow waves of non-REM deep sleep

  • Deep sleep allows you to save memories in the brain

  • Non-REM deep sleep is divided into four stages, increasing in the depth of sleep: stages 1 and 2 are light stages of non-REM deep sleep; stages 3 and 4 are deep stages of non-REM deep sleep

  • In stages 1 and 2: heart rate begins to drop, brain wave activity slows down

  • In stages 3 and 4: heart rate is low, cells in cortex fire together then go silent

Hormone Regulation During Sleep Cycles

  • Sleep should be evolutionarily selected against as during sleep we are vulnerable to predation which one could imagine would have made sleep selected out – but it hasn’t so it must serve a significant function

  • Hormone regulation and dysfunction are different during non-REM deep sleep and REM sleep

  • During non-REM deep sleep, we get autonomic restoration and regulation of heart rate and blood pressure

  • Insulin regulation of metabolism is disrupted in cases where non-REM deep sleep is insufficient

  • Growth hormone and testosterone are tied to REM sleep

Sleeping The Whole Night Through Versus Involuntary Disruptions To Sleep

  • Sometimes you will wake up in the middle of the night for some reason – maybe to use the restroom, maybe you just wake up

  • It’s natural to wake up in the middle of the night, especially with age

  • When we finish 90-minute cycles, almost everyone wakes up and changes position because the body has been paralyzed in REM

  • Healthy sleep efficiency: of the total amount of time in bed, we want to be asleep approximately 85% or more asleep

  • Intervene in fragmented sleep if you are waking up 6-7 times per night, or if wakeful periods are 20-25 minutes

  • Uberman schedule: person sleeps in 90-minute bouts throughout day and night

  • If you sleep in accordance with the natural sleep cycles mother nature gave us, your health will be better

Light Exposure

  • Stack cues for wakefulness early in the day

  • In the first half of the day, get at least 30-40 minutes of direct sunlight each morning to feel more alert – can do this even by working next to a window with natural light coming through

  • Sleep time and efficiency can increase dramatically if you are working in an area with a window

  • If you can do it safely, minimize the time in sunglasses to accurately convey information about time and day to the rest of the body


  • It’s best to allow natural signals to wake up the body by delaying caffeine intake 90 minutes after rising

  • How does caffeine work to wake us up: caffeine is a psychoactive stimulant that increases dopamine and blocks adenosine (which makes us sleepier)

  • Caffeine crash: when coming down from caffeine, you lose the effects of caffeine, and the level of adenosine you suppressed comes rushing in

  • The dose and timing of coffee is what makes it helpful or harmful

  • The half-life of coffee is 5-6 hours depending on liver enzyme

  • Even if you don’t feel the effects of late caffeine intake on sleep, cycles will likely be disrupted – particularly deep sleep

  • You might fall asleep and stay asleep well, but increase caffeine intake the next day because you don’t feel rested

  • Suggestion for last caffeine intake: 8-10 hours from the time you would like to sleep


  • Alcohol is a sedative but not a sleep-aid

  • People tend to turn to a “nightcap” or evening drink to help them fall asleep and turn off thoughts and planning

  • Negative impacts of alcohol on sleep:

  • You lose consciousness quicker but are not achieving quality sleep

  • Alcohol fragments sleep so you will wake up many times throughout and will not have continuous sleep

  • Alcohol is a potent REM sleep blocker