Dr. Matthew Walker on Sleep for Enhancing Learning, Creativity, and Immunity – Found My Fitness with Dr. Rhonda Patrick

Check out the Found My Fitness Episode Page & Show Notes

Watch the episode here

Key Takeaways

  • Deep sleep is essential for cementing memories and information
  • REM (rapid eye movement)/dream sleep helps to form connections between recently learned information and our entire back catalog of memories
  • If you’re thinking about pulling an all nighter to study for an exam…don’t
  • Playing the same sound at a sub-threshold awakening level while you learn and sleep seems to improve memory retention
  • Here’s what happens when you don’t get enough sleep:
    • Your regulation of blood glucose is profoundly impaired
    • “In my lab, the most reliable thing we see when we deprive people of sleep of any dose – anxiety goes up”
    • Men who are sleeping 5 hours or less a night will have a level of testosterone that of 10 years their senior
    • Your risk of developing Alzheimer’s disease skyrockets 
    • In one study, participants restricted to 4 hours of sleep for just ONE night experienced a 70% reduction in natural killer cell activity
      • Natural killer cells are a critical part of your immune defense arsenal
    • When you’re sleep deprived, you have a lowered desire for social proximity and social interaction
      • You’re also more likely to appear as a “lonely person” when sleep deprived and people are less likely to engage with you
      • “Being lonely increases your mortality risk by 45%” – so being lonely is twice as risky for your death concern as obesity
    • Relative to a person with a full night’s sleep, the amygdala (the emotional part of the brain) is 60% more reactive under conditions of a lack of sleep
      • And on top of that – sleep deprivation shuts down the prefrontal cortex’s communication with the amygdala (the prefrontal cortex acts as a break on the gas pedal of your emotions)
  • People with insomnia have an amplified fight or flight nervous system (aka the sympathetic nervous system)
  • As we age, the amount of deep sleep we get decreases
    • By the time you’re 50, you’re getting about 50% less deep sleep compared to your teens
  • When sleep trackers are compared to actual data gathered in lab sleep studies – “they’re not quite accurate”
  • Here’s how typical sleep cycles work:
    • Deep non-REM sleep always comes before REM sleep
    • This repeats every 90 minutes throughout the night
      • As the night goes on, the ratio of REM to non-REM/deep sleep changes
        • In the first half of the night, the majority of those 90 minute cycles are comprised of lots of deep sleep, and little REM
        • In the second half, you get much more REM sleep and little deep sleep
        • So….if you typically go to bed at 12 AM and wake up at 8 AM, but have to wake up at 6 AM one morning – yes you’ve lost 25% of your sleep duration, but you’ve lost perhaps 80% of your REM sleep
          • The same happens if you go to bed too late – you miss out on valuable deep sleep
  • Sleep tips:
    • Aim to get lots of light during the day and lots of darkness at night
      • An hour before bed, it’s a good idea to dim or turn off most of the lights in your house
      • Avoid blue light too close to bedtime (specifically the hour before bed)
    • For you to fall asleep and stay asleep, your body has to drop its core temperature 1 °C (2-3 °F)
      • To help lower your core body temperature – take a hot bath/shower before bed (or use the sauna)
        • Why? – When you get into a hot bath, you get massive vasodilation
          • All the blood vessels open up on the surface of your skin – this results in a rush of blood from the core of your body to the surface, so your skin/hands/feet act as a thermal radiator and dissipate body heat, thus lowering your core body temperature
          • Wearing socks to bed also does something similar
      • Try to set your bedroom temperature between 63 to 66 °F
    • Don’t stay in bed if you can’t fall asleep
    • Know that alcohol suppresses REM sleep
      • (So does cannabis – specifically the psychoactive ingredient in cannabis (tetrahydrocannabinol -THC) – although it may reduce the time it takes you to fall asleep)
      • Related:
        • Low doses of cannabidiol (CBD) seem to promote wakefulness
        • High doses of CBD seems to help people sleep more consistently
    • Avoid caffeine after midday

Products Mentioned

  • Rhonda uses Phillips Hue light bulbs throughout her house which shine red light starting ~5 PM (it’s essentially the opposite of blue light – it’s similar to darkness)
  • In studies where participants wore a specialized temperature controlled suit which lowered their core body temperature, they fell asleep quicker and deep sleep amounts increased 10-20%
    • Because of this, Dr. Walker thinks something like a Chilipad might be able to increase the time you spend in deep sleep and help you fall asleep faster

Intro

  • Dr. Matthew Walker (@sleepdiplomat) is the author of Why We Sleep and professor of neuroscience and psychology at the University of California, Berkeley
    • Rhonda HIGHLY recommends the book – we do too
    • Check out Dr. Walker’s website
    • Check out the Podcast Notes from his appearance on Joe Rogan, as well as the Podcast Notes from his appearance on The Jordan Harbinger Show
      • His Joe Rogan podcast won our 2018 Podcast of the Year Award
  • The circadian rhythm has many genetic components, some of which you can measure with 23andMe and Ancestory DNA 
  • Check out FMF Clips
    • They’re Youtube clips from the Found My Fitness podcast (including this one)

Sleep and Learning

  • Sleep seems to be important in 3 ways:
    • You need sleep prior to learning to prep the brain for soaking up new information/laying down new memory traces
    • You need sleep after learning to take those new memories, particularly in the hippocampus region of the brain (aka the informational inbox of the brain), and essentially hit the save button on them
      • This consolidates the memory/what you learned
      • What’s actually happening? – It’s almost like there’s a file transfer going on
        • Memories are shifted from the short-term/vulnerable storage reservoir (the hippocampus – which acts like a USB stick) and moved to the long-term storage site in the brain (the cortex – which acts like a computer hard drive)
          • A side benefit of this – the hippocampus (the USB stick) is cleared, so the next day you can start acquiring new files/memories/information
      • “You can’t cheat sleep on either side of the memory equation”
    • You need REM (rapid eye movement sleep)/dream sleep for a few reasons:
      • “It’s a little bit like group therapy for memories”
      • REM sleep fuses the information you’ve recently learned with your entire back catalog of memories
        • “REM sleep is essentially creating a revised mind wide web of associations”
      • During the day, our brain makes obvious connections
        • But during REM sleep, this is where we really make those bizarre connections
        • Here’s how Dr. Walker explains it:
          • During the day, it’s like a Google search gone right. You search something, and what you see what’s on page 1 of the search results. But during REM sleep, it’s like you search something and jump straight to page 20.
          • “We now understand that it’s REM sleep that helps up come up with remarkable creative insights into previously impenetrable problems”
  • Let’s recap:
    • Deep sleep is about knowledge – gathering information and holding on to it
    • REM sleep is about wisdom – knowing what it all means when you fit it together

Does pulling an all nighter ever make sense?

  • “You can’t pull an all-nighter and hope to be able to continue to learn”
  • Dr. Walker describes a study he and his research team did:
    • Two groups were created: a well-rested group (aka the sleep group) who had a full 8 hours rest and a sleep deprived group who were kept awake all night with no caffeine
    • The next day, everyone in the study was placed inside an MRI scanner and instructed to learn a list of new facts
    • The sleep deprived group was 40% more deficient in their learning ability – so they learned 40% less (this is the difference between acing and failing an exam)
    • In the group of people who had a full night of sleep, there was lots of healthy learning related activity in the hippocampus
      • In the sleep deprived group, there was none – “It’s almost like sleep deprivation served to shut down your memory inbox and any new incoming files were being bounced”
        • Why? – It’s hypothesized that the hippocampus has a limited storage capacity (like a USB stick)
        • In humans, it seems we only have a 16 hour recording capacity for information acquisition before we have to sleep

During Sleep Your Brain “Replays” What You Learned That Day

  • Dr. Walker recalls a study done with rats:
    • Electrodes were placed on the hippocampus region of a rat’s brain
    • As the rat ran around the maze and learned its format, individual cells in the hippocampus would fire, and spatially code which part of the maze the rat was in – Different cells were mapping different parts of the journey
    • Electrode activation was able to be linked to a specific sound – this created a certain audio pattern played as the rat went through the maze
      • That SAME audio pattern was heard (but at 10-20x the speed) once the rat started sleeping – indicating the rat’s brain was replaying the sequence of the maze/what they learned about it
        • So the SAME electrical pattern in the rat’s brain was played while they were sleeping as when they were learning the maze, just much faster
        • What stage of sleep did this occur in? – Deep sleep

How Sound Can Improve Memory Retention

  • If you were to try to learn the spatial location of certain objects on a screen…
    • And after a night of sleep, you’d be asked:
      • Did you recall seeing this object?
      • Where was it on the screen?
    • If certain sounds were played when certain objects were shown (like the sound a cow makes if a cow was shown) and those same sounds were replayed while you slept…
      • Compared to objects/sounds that were not replayed while you slept, your memory retention would be about 2x better
      • (The sounds have to be played at a “sub-threshold awakening sound level so as not to wake you/disrupt your sleep)

Study Tips

  • Given how playing certain sounds while you sleep improves memory retention…
    • Perhaps you should study while listening to a series of songs. Then, while you’re sleeping, replay those same songs at a very low volume.
  • If you study in the same room you plan to take an exam in, you’ll perform better
    • Why? – You’ll subconsciously use cues from around the room as memory triggers to help you remember things better
  • If you learn something, and then sniff a certain odor – you’ll associate what you learned with that odor
    • Then, while you’re sleeping, the odor is perfused up your nose, your memory retention improves two fold

Dreaming

  • Why do you only sometimes remember your dreams?
    • If you wake up during dream sleep, and then go back to sleep, you’re more likely to remember what you were dreaming about
    • Dr. Walker has a theory that we “remember” all of our dreams, they’re just not accessible
      • “What happens when we wake up is we lose the IP address to those memories”
      • “It’s almost a scary prospect – maybe every single one of our dreams we’ve had in our lives are stored and determine our behavior to some degree”
  • EVERYONE dreams
    • Except for people who have a lesion in a certain part of the prefrontal cortex in their white matter (these are informational fiber tracks that communicate impulses)

Sleep and Loneliness

  • Dr. Walker just published a study demonstrating that sleep loss can trigger viral loneliness. Here’s what the study found:
    • Sleep deprived people (with no sleep) , compared to those who get a full 8 hours, have more of a “social repulsion boundary”
      • What does this mean? – It’s just your willingness to tell someone they’re getting too close to you physically
        • For this reason, when you’re sleep deprived, you have a lowered desire for social proximity and social interaction
      • What’s going on here on the level of the brain?
        • The “alarm” regions of the brain, in the parietal cortex and premotor cortex (aka the “stay away from me” network – it creates your comfort of boundary) became hyperactive when people were sleep deprived
    • Sleep deprivation shuts down the parts of the brain which help you understand the intents of other people
    • You’re more likely to appear as a “lonely person” when sleep deprived
    • People are less likely to engage/interact with you when you’re sleep deprived
      • It’s due to a collection of things – appearance, vocal tone
    • Even reductions in sleep of minute to hours can predict how lonely you experience yourself to be from one day to the next
    • So in summary:
      • When you’re sleep deprived, you are less apt to associate with other people, and people find you more socially repulsive – there’s a push from both sides of the social died
  • A bit of background from other studies:
    • When you’re sleep deprived, cortisol (the stress hormone) increases, there’s a shift in insulin/glucose regulation, and anxiety increases
    • Sleep deprived animals seem to isolate themselves 
  • Facts
    • There is a massive epidemic of loneliness in industrialized nations
    • “Being lonely increases your mortality risk by 45%”
      • So being lonely is twice as risky for your death concern than obesity
    • Rhonda recalls a study showing that loneliness increases the expression of many pro-inflammatory genes
    • When you become lonely, your gene expression shifts you away from a profile of immunity that normally deals with viruses and pushes you more towards a bacterial defense profile
      • Viruses can only be transmitted from one person to another by way of touch
      • Bacteria on the other hand, can live outside the body

Sleep and Emotions

  • Relative to person with a full night’s sleep, the amygdala (the emotional part of the brain) is 60% more reactive under conditions of a lack of sleep
    • And on top of that – sleep deprivation shuts down the prefrontal cortex’s communication with the amygdala (the prefrontal cortex acts as a break on the gas pedal of your emotions)
      • (The prefrontal cortex is like the CEO of your emotions/hedonic impulses)
  • The above is similar to the signature of many psychiatric conditions
    • “We have not been able to discover a single psychiatric condition in which sleep is normal. Sleep has a PROFOUND story to tell in our understanding, and maybe even our treatment, of grave mental illness.”
    • “It’s always been documented that sleep disturbance goes hand in hand with psychiatric disturbance.”
  • Let’s add…
    • Certain genes predispose you to anxiety 
      • So if you’re a highly anxious person, and sleep deprived….uh oh – you’re the most vulnerable to a lack of sleep and its effects on emotional control
        • This is troublesome because anxiety itself can contribute to a lack of sleep

Insomnia and Cortisol

  • There are two types (not mutually exclusive):
    • Difficulty falling asleep (sleep onset insomnia)
    • Difficulty staying asleep (sleep maintenance insomnia)
  • You constantly see an amplified fight or flight nervous system (the sympathetic nervous system) in people with insomnia
    • The sympathetic nervous system regulates cortisol release
      • At night, our cortisol levels typically fall
        • People with insomnia don’t get as significant as a cortisol drop (it actually rises)
      • Throughout the night cortisol drops even further
        • In people with sleep maintenance insomnia, there’s a cortisol spike during the night, causing them to wake up
  • Meditation seems to help fight insomnia 
    • Why? – Meditation helps settle the overactive sympathetic nervous system
  • 6 hours of bright light exposure during the day has been shown to lower cortisol by 25%

The Circadian Rhythm and Light

  • Everyone is wired to have a dip in their alertness level come mid-afternoon
  • To align your circadian rhythm optimally (so you’re awake/active during the day, and sleepy at night), here’s what you should know:
    • Get lots of daylight during the day and lots of darkness at night
      • “We are a dark deprived society in the evening and a light deprived society during the day”
      • Darkness triggers the release of melatonin (a hormone which tells your body it’s time to sleep)
      • Try to get as much light as you can first thing in the morning (aim for 30-40 minutes) – Do NOT wear sunglasses
        • Your eyes need the light
        • In the afternoon though, go ahead and wear sunglasses, especially the later in the afternoon it gets
        • Even on a cloudy day, the lux intensity of light far exceeds that from you’d have from light inside a building – so just go outside more!
        • At night, just turn off most of the lights in your house the hour before bed
    • Other tips:
      • Rhonda uses Phillips Hue light bulbs throughout her house which shine red light starting ~5 PM (it’s essentially the opposite of blue light – it’s similar to darkness)
  • As you age, your circadian rhythm gets weaker
    • So you feel sleepier during the day and not as tired at night

Sleep and Temperature

  • “Temperature is as powerful a trigger of sleep organization and sleep depth as light is”
  • For you to fall asleep and stay asleep, your body has to drop its core temperature 1 °C (2-3 °F)
  • Hunter gather tribes tend to go to bed around 8-9 PM (when the temperature starts to drop shortly after sunset)
    • They typically wake up 15-20 minutes before dawn when the temperature starts to rise
  • In studies where participants wore a specialized temperature controlled suit which lowered their core body temperature, they fell asleep quicker and deep sleep amounts increased 10-20%
    • Because of this, Dr. Walker thinks something like a Chilipad might be able to increase the time you spend in deep sleep and help you fall asleep faster
  • Another tip  – take a hot bath/shower before bed (or use the sauna)
    • Why? – When you get into a hot bath, you get massive vasodilation
      • All the blood vessels open up on the surface of your skin – this results in a rush of blood from the core of your body to the surface, so your skin/hands/feet act as a thermal radiator and dissipate body heat, thus lowering your core body temperature
      • Wearing socks to bed also acts to do something similar

Saunas, Exercise, the Immune System, and Sleep

  • One of the ways you can induce sleep is to increase the body’s immune factors (cytokines, tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), interleukin -1 (IL-1)
    • And….sauna use has been shown to increase a variety of these
  • If you inject an animal with a pathogen, it creates an immune antibody response (aka a cytokine cascade)
    • Those cytokines communicate with the hypothalamus which regulates sleep
    • This immune cascade triggers an increase in sleep
      • This is why when we’re sick, we get sleepier
  • Building off the above – here’s how exercise might help your sleep
    • Exercise results in acute production of proinflammatory cytokines
  • For more on the link between sauna use, exercise and IL-6 check out these Podcast Notes

Getting Back to Our Origins – How much sleep do we need?

  • Between 7-9 hours
  • But it’s been found that when you isolate people, with no electricity, no alarm clocks (essentially have them go camping) – they tend to sleep closer to 9 hours
    • In experiments like this, people also tended to go to bed earlier, and wake up earlier
  • The term “midnight” originated from the idea that it was actually …the middle of the night/sleep cycle
    • Now it’s when most people check social media for the last time

A Lack of Sleep and the Immune System

  • In one study, participants restricted to 4 hours of sleep for just ONE night experienced a 70% reduction in natural killer cell activity
    • Natural killer cells are a critical part of your immune defense arsenal
  • If you typically get less than 6 hours of sleep a night, your risk for a variety of cancers (bowel, prostate, breast, and more) increases
  • The link between a lack of sleep and cancer is now so strong that the World Health Organization recently classified any form of nighttime shift work as a probable carcinogen
  • It’s been found that if you’re getting 5-6 hours of sleep a night the week prior to getting a flu shot, you only produce ~half of the normal antibody response, rendering the flu shot largely useless
    • The flu virus costs the United States ~$10 billion every year

Sleep and Alzheimer’s Disease

  • Rhonda has one copy of the ApoE4 allele (25% of the U.S. population has at least one allele) – it’s just a gene, you can see how many alleles you have with a 23andMe DNA test
    • People with one allele have a 2-3 fold higher risk of Alzheimer’s Disease
    • People with two alleles have a 10-15 fold higher risk of Alzheimer’s Disease
  • The build up of two proteins seem to contribute to Alzheimer’s disease:
    • Beta-amyloid – leading to amyloid plaques
    • Tau protein – leading to “tau tangles”
  • Let’s examine beta-amyloid more closely:
    • It seems to build up in certain areas of the brain more than others 
      • One of the earliest places it builds up- the medial prefrontal cortex
        • The principal epicenter that generates your deep sleep sits at this same spot – it’s been found that the more beta-amyloid builds up, the less deep sleep you get, and the more blunted your learning/memory ability becomes
          • And remember the function that deep sleep serves? – It helps to cement memories
          • Related – As we age, the amount of deep sleep we get decreases
            • It starts to decline as early as your 20s
            • By the time you’re 50, you’re getting about 50% less deep sleep compared to your teens
            • By the time you’re 70, you’re getting about 5% of the deep sleep you were getting in your teens
            • And 80….you’re hardly getting any
  • But how about the reverse? – Good sleep seems to reduce the build up of amyloid plaques
    • How? Dr. Walker explains:
      • The glymphatic system is essentially the sewage system of the brain – it clears away “gunk”
      • During deep sleep, brain cells shrink by 60%, creating huge channels for the glymphatic system to clear away the metabolic waste of the brain through the squirting of cerebral spinal fluid 
        • Through a pulsatile mechanism, there’s a 10-20% increase in the “squirting” of cerebral spinal fluid through the brain during sleep which washes away the brain’s metabolic byproducts
          • And one of those metabolic byproducts? – Beta-amyloid
  • How bad does it get?
    • Just depriving someone of deep sleep (by playing certain tones/sounds, which won’t wake you up, but will take you out of deep sleep) for ONE night, will result in a rise in the amount of beta-amyloid in the brain by 25-30%
  • Related:
    • People who have even one Apoe4 allele have a significant risk of sleep apnea (heavy snoring and cessation of breathing, causing you to wake up)
      • Sleep apnea increases the risk of cardiovascular disease, stroke, diabetes, and obesity
      • People with sleep apnea have lowered amounts of deep sleep
  • In summary:
    • Insufficient sleep is one of the most significant lifestyle factors that contributes to Alzheimer’s disease

Sleep Trackers and The Oura Ring

  • For more on the Oura Ring check out these Podcast Notes
  • How accurate is it? It’s just a ring – are the levels of deep sleep, REM sleep, and light sleep it gives you accurate?
    • It calculates all these through some sort of algorithm combining heart rate and your body’s movement
    • “Right now, I don’t think there’s any one [sleep tracker] that’s better than the others. None of them have published scientific evidence.”
    • When sleep trackers are compared to actual data gathered in lab sleep studies – “they’re not quite accurate”
      • The most accurate of the measurements – sleep duration
      • Their ability to calculate REM, deep sleep etc. – ehhhhh – Dr, Walker estimates it’s about 60% accurate, possibly lower
        • But they’re getting better…

More Benefits of REM Sleep

  • It acts as “emotional first aid”
    • “It’s not time that heals all wound, but time spent during REM sleep”
    • Dr Walker explained this more in these Podcast Notes
  • REM sleep also acts to increase heart rate variability (HRV) which is used as a metric of health outcome
    • High HRV is good

The 4 Pillars of Sleep

  • (Dr. Walker is planning another book about this)
  • Depth/Quality
    • This has to do with the brain waves produced during the different stages of sleep (you need the electrical brain wave stimulation from ALL stages)
  • Duration
    • 7-9 hours, non-negotiable
  • Continuity
    • This has to do with waking up during the night, which you want to reduce
    • You don’t want fragmented sleep
      • 8 hours continuous sleep > 8 hours of sleep in a 9 hour window
  • Regularity
    • Go to bed and wake up at the same time, every…single….day

Chronotypes

  • This is the term which describes whether you’re a night owl, a morning person (a morning lark), or somewhere in the middle
    • ~30% of people are morning larks, 30% night owls, and 30-40% in the middle
  • Your chronotype is genetic
    • It’s not your fault if you can’t wake up at 6 AM 😉
  • How your chronotype relates to REM and deep sleep:
    • In typical sleep cycles, deep non-REM sleep always comes before REM sleep
      • It’s not known why this is the case
    • This repeats every 90 minutes throughout the night
      • As the night goes on, the ratio of REM to non-REM/deep sleep changes
        • In the first half of the night, the majority of those 90 minute cycles are comprised of lots of deep sleep, and little REM
        • In the second half, you get much more REM sleep and little deep sleep
    • So….if you typically go to bed at 12 AM and wake up at 8 AM, and have to wake up at 6 AM one morning – yes you’ve lost 25% of your sleep duration, but you’ve lost perhaps 80% of your REM sleep
      • The same happens if you go to bed too late – you miss out on valuable deep sleep
      • (Here’s an interesting point – many night owls, who are forced to wake up early for work, tend to experience higher rates of depression and anxiety. Why? Reduced amount of REM sleep.)
  • In summary – “Fighting your chronotype comes with deleterious health consequences”
    • These include – higher levels of c-reactive protein (an inflammatory marker), increased risk for metabolic diseases, higher long-term blood glucose levels, increased risk of obesity, shorter telomeres

Sleep and Blood Glucose Regulation

  • People who sleep <7 hours/night have a much higher risk of developing type 2 diabetes
  • After one week of getting 4-6 hours of sleep a night – “Your blood sugar levels are disrupted so significantly that your doctor would classify you as pre-diabetic”
    • This is calculated with an oral glucose tolerance test
    • Without sufficient sleep, the beta cells in your pancreas (which produce insulin – this is the hormone which shuttles glucose out of the blood and into the cells that need it) have a reduced sensitivity to glucose spikes – so less insulin is released 
    • AND – cell receptors throughout the body become less sensitive to insulin (so less glucose is shuttled into the cells)
  • What specifically is responsible for this reduction in the body’s ability to create/sense insulin?
    • The reduction in deep sleep
  • In summary – “Your regulation of blood glucose is profoundly impaired by a lack of sleep”

It Gets Even Worse…

  • With a lack of sleep, your hunger hormones are very impaired
    • Leptin (the hormone that signals satiety/fullness) doesn’t rise as high as it should after a meal
    • Ghrelin (the hunger hormone) increases
  • When you’re sleep deprived:
    • You tend to overeat (by 200-300 calories per meal) and snack much more often
    • You choose to eat more starchy carbohydrates and sugary foods – these are the foods that really lead to weight gain
  • All of this leads to an increased risk of obesity

Sleep and the Microbiome

  • There are similarities between the gut microbiomes of people who are obese and people who are sleep deprived (or jet lagged)
    • They have higher levels of a certain phylum of bacteria (Firmicutes) and lower levels of another phylum (Bacteroidetes)
  • Side note – bacteria in the microbiome have their own circadian rhythm
  • Sleep deprivation leads to higher cortisol levels
    • Cortisol has been shown to produce microbiome imbalances (shifting to a more obesity-type profile)
  • The vagus nerve connects the gut to the brain – this is another possible way the gut biome is affected by sleep
    • Rhonda recalls a study examining a certain strain of bacteria (rhamnosus) which produces GABA in the gut (but GABA doesn’t cross the blood brain barrier – the brain has GABA though, it’s made there) – through the vagus nerve, the brain was shown to increase production of GABA (which aids sleep quality)
  • Other cool gut biome facts
    • There have been studies showing that taking a probiotic high in the same strain of bacteria mentioned above (rhamnous) decreases anxiety

A Lack of Sleep Leads to Anxiety

  • “In my lab, the most reliable thing we see when we deprive people of sleep of any dose – anxiety goes up”
    • Past 14-15 hours of wakefulness, anxiety increases
    • The further you go into sleep deprivation – the more anxious you become

Sleep Tips

  • Try to stay in dark environments at night 
    • This helps with the release of melatonin (which triggers the onset of sleep)
    • Start thinking about avoiding light 3-4 hours before bed, but definitely the hour before bed
    • Avoid blue light too close to bed time (specifically the hour before bed)
      • Use f.lux if you have to use your computer (but try to avoid doing so)
      • One hour of iPad (or any phone) use before bed has been shown to blunt melatonin levels by 20% and delay peak melatonin levels by 3 hours
        • It also resulted in less REM sleep
  • Try to set your bedroom temperature between 63 to 66 °F
  • Don’t stay in bed if you can’t fall asleep
    • If it’s been more than 20 minutes, get up and go read a book in dim light
    • The whole point of this – you don’t want your brain to have any association with being awake in bed
  • Try to avoid caffeine after midday
    • If you give someone a cup of coffee (~200 mg of caffeine) in the evening, the amount of deep sleep they get is reduced by 20%
    • Caffeine has a half-life of 5-6 hours, but a quarter-life of 12 hours
      • If you have a cup of coffee at 12 PM, a quarter of that caffeine is still circulating in your brain at midnight (this is the equivalent to drinking a quarter cup of coffee right before bed)
  • Know that alcohol suppresses REM sleep
    • (So does cannabis – specifically the psychoactive ingredient in cannabis (tetrahydrocannabinol -THC) – although it may reduce the time it takes you to fall asleep)
    • “Alcohol is a sedative and sedation is not sleep”
    • Alcohol also causes you to wake up more often throughout the night
  • In general – avoid using something daily to help you get to sleep
    • Treat the root cause, don’t medicate

What about Cannabidiol (CBD)?

  • Here’s a brand of CBD we recommend at Podcast Notes
  • It doesn’t seem to restrict REM sleep
  • Low dose CBD seems to promote wakefulness
    • High dose CBD seems to help people sleep more consistently

Sleeping Pills and Ambien

  • “Sleeping pills come with deathly consequences and high risk of cancer”
  • In the path month, 10 million Americans have used a sleeping aid (either prescription or over the counter)
  • Ambien (and other sleeping pills) just sedate the brain – it’s not true sleep
    • They also create lots of grogginess in the morning
    • AND they increase susceptibility to infection (particularly pneumonia)
  • “There is a non-pharmacological treatment that is just as effective as sleeping pills in the short-term. It is completely safe and it’s more advantageous in the long term – cognitive behavioral therapy for insomnia (CBTI).”

Sleep Quotes

  • “Sleep is the Swiss Army knife of healthy. No matter what the ailment, there is something more than likely in sleep’s toolbox that will deal with it.”
  • “There is no physiological system that we’ve been able to measure that isn’t wonderful enhanced by sleep when you get it or demonstrably impaired when you don’t get enough”
  • “The shorter your sleep, the shorter your life”
    • “Short sleep predicts all cause mortality”
  • “EVERY single disease that’s killing us in the developed world has causal links to a lack of sleep”
  • “Sleep is a life support system and it’s mother nature’s best effort yet at immortality”

Random, But Oh So Important

  • Let your child nap
    • After an infant naps (compared to an infant that hasn’t) they’re better able to extract and understand the overarching rules of what they’ve been learning, not just the individual facts
      • Infants that haven’t napped after learning, are not quite as able to make that abstraction
  • Men who are sleeping 5 hours or less a night will have a level of testosterone that of 10 years their senior
    • This effect happens with just a few consecutive nights of 5 hours of sleep
  • Deep sleep seems to “provide a homeostatic recalibration of blood pressure”
    • The amount of deep sleep you get predicts how much of drop in systolic blood pressure you have in the morning relative to the evening
  • ALL states of sleep are important
    • Otherwise, over the course of billions of years of evolution, it would have been removed
  • A sleep tip –  always try to get the sleep duration you need (so if you go to bed late, sleep in)
  • People who eat a diet high in processed carbs and low in fiber, tend to have lower amounts of deep sleep, take longer to fall asleep, and awake more throughout the night
  • 1 out of every 2 adults in first world nations is chronically sleep deprived
  • Most doctors get <2 hours of sleep education during the medical curriculum 

These notes were edited by RoRoPa Editing Services

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