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
Caffeine
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
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