Sleep Is Non-Negotiable: Dr. Matthew Walker | Rich Roll Podcast

Key Takeaways

  • “Sleep is not an optional lifestyle luxury, it is a non-negotiable biological necessity. It is your life support system.” – Dr. Matthew Walker
  • Short sleep has damaging effects on the cardiovascular system, weight, diabetes, Alzheimer’s, immune function, memory, and mood
  • If you deprive a healthy adult of sleep or deep sleep for just one night – there’s an immediate increase in beta-amyloid proteins (present in Alzheimer’s)
  • We’ve learned more about sleep in the past 50 years than we have in the previous 5,000 years
  • Figure out chronotype and sleep in accordance with that – don’t get sucked in to “rise and grind” culture – it doesn’t work for everyone
  • “The shorter your sleep, the shorter your life. Short sleep predicts all-cause mortality.” – Dr. Matthew Walker
  • Anxiety is the principal cause of anxiety – for better sleep, get physical activity and deal with anxiety non-pharmacologically (try meditation)
  • “Is there any system in the body or mind that isn’t wonderfully enhanced when we get sleep and isn’t demonstrably impaired when we don’t? The answer seems to be no.” – Dr. Matthew Walker
  • “Sleep is the single most effective thing we can do each day to reset our brain and our body.” – Dr. Matthew Walker
  • For better sleep, control: temperature, regularity, caffeine and alcohol intake, exercise, and physical activity
  • Teens and adolescents need more sleep – they’re not just lazy
  • Naps are a double-edged sword: if you have trouble sleeping, do not nap; if you sleep well at night napping before 2 pm is ok
  • Melatonin can be used when traveling through different time zones to acclimate but not recommended as a daily supplement
  • People who only sleep with sleeping pills experience rebound effects in which sleep is actually worse when they stop


Matthew Walker, Ph.D. (@sleepdiplomat) is a sleep expert and Professor of Neuroscience and Psychology at the University of California, Berkeley, USA. He is also the founder and director of the Center for Human Sleep Science.

In this episode of Rich Roll Podcast, Matthew Walker and Rich Roll take a deep dive into all things related to sleep: why we sleep, why it’s important, what happens when we sleep, implications of sleep deprivation, and much more. They also provide actionable takeaways to improve sleep hygiene and offer tips for altering various stages of sleep.

Book: Why We Sleep by Matthew Walker, PhD

Host: Rich Roll (@richroll)

Evolutionary Paradox Of Sleep

  • The evolutionary advantage of sleep is perplexing
  • During sleep we are vulnerable to predation which one could imagine would have made sleep selected out
  • If we consider evolution, the traits that persist are usually related to speed, ability to hunt and gather, and strength
  • The fact that sleep evolved with life itself means sleep must serve a critical evolutionary function
  • Non-rapid eye movement deep sleep was the first sleep to emerge
  • We experience things during sleep that we can’t experience in wakefulness

Societal Narrative Around Sleep

  • Society stigmatizes sleep as lazy
  • Many of us experience gradual chipping away of sleep time
  • We don’t want to shortchange on time with family, friends, relaxation, etc. – so we sacrifice sleep
  • Zero people can survive on five hours of sleep or less with no repercussions – we just train ourselves to think we’re ok or that we don’t need much sleep
  • Short sleep or insufficient sleep clouds judgment of our experience and necessity of sleep hours
  • The deficient form of yourself becomes the new norm
  • The Guinness Book of World Record prohibits sleep deprivation records because of significant harmful side effects
  • Effects of sleep deprivation: psychosis, personality changes, changes in appetite, memory loss, and emotional instability
  • It’s damaging to think we can hack sleep

Sleep Cycles In Humans

  • Two main types: non-rapid eye movement sleep (non-REM) and rapid eye movement (REM)
  • Non-REM sleep has four cycles:
    • Stages 1 and 2 are light stages of sleep
    • Stages 3 and 4 are deep stages of sleep
  • REM sleep is the stage in which we dream and effectively overnight therapy
  • When you go into REM dream sleep, the brain paralyzes the body so you won’t act out your dreams
  • Deep sleep allows you to save memories in the brain
  • Non-REM and REM play for brain domination throughout the night in 90-minute cycles
  • 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
  • Because of the 90-minute cycles, it makes a difference when we shift our sleeping pattern to sleep later or wake up earlier
  • All stages of sleep are critical but there is some research suggesting REM sleep may be slightly more important for staving mortality
  • Parasomnia: disorders that happen around sleep which cause sleep talking or sleepwalking
  • Incidence of sleepwalking and sleep talking are much higher when we are younger and most outgrow it
  • Sleep saves memories and stitches old and new experiences together
  • People on SSRIs and anti-depressants show a reduction of REM sleep
  • You don’t decide whether you are a morning person or a night owl – your chronotype and genetic disposition determines that

Importance Of Sleep For Biological Health

  • Sleep has a cascade of important health benefits
  • Sleep isn’t the pillar of health – it’s the foundation
  • Sleep dwarfs physiological and mental deficits that come with poor diet or exercise
  • Operations of the mind are overhauled during sleep
  • The brain is up to 30% more active during sleep than when awake
  • There is no mental health condition in which sleep is normal
  • 1 out of every 3 people are not getting enough sleep
  • CDC recommends a minimum of 7 hours of sleep per night to maintain health
  • Just one night of dysregulated sleep per week has deleterious effects
  • Lack of sleep in men causes testosterone drops equivalent to ten years of aging
  • Lack of sleep in women is damaging to menstrual cycles and fertility health
  • Lack of sleep can induce a pre-diabetic state
  • With even 6 hours of sleep per night, studies have shown a distortion in gene expression (either turned off or overexpressed) of genes associated with the promotion of tumors, metabolic control
  • “This is a little bit extreme but biologically accurate: wakefulness is low-level brain damage and sleep is sanitary salvation.“ – Dr. Matthew Walker
  • Lack of sleep increases dopamine centers and impulsivity increases – far more likely to develop addiction disorder or relapse

Sleep, COVID-19 & Immunity

  • There’s an intimate association between sleep health and immune health
  • Individuals who sleep less than 7 hours per night are almost 3x as likely to contract rhinovirus (common cold)
  • Women sleeping 5 hours or less per night are more than 60% more likely to develop pneumonia
  • If you don’t get enough sleep in the week before a flu shot, you will not confer same level of antibody response
  • Sleep provides two benefits for immunity: (1) the body produces critical immune factors in deep sleep; (2) sleep increases sensitivity and receptivity of the body to immune factors
  • COVID-19 has impacted sleep quantity, quality, timing, dreaming
  • On average, sleep duration has increased 20-30 minutes during COVID-19
    • But – there is a subset of people for whom sleep is worse because of stress, fear, etc.
  • People are going to bed later and waking up later – people are sleeping in synchrony with chronotype
  • Anecdotally, people are dreaming more

The Link Between Lack Of Sleep And Alzheimer’s Disease

  • In general, sleep is critical in memory
  • Research showed a loss of memory structure in the brain’s hippocampus in airline pilots whose schedules induce sleep dysregulation because of the time change and flight times
  • People who sleep less than 6 hours per night develop far more proteins underlying Alzheimer’s disease
  • People with sleep disorders such as insomnia are far more likely to develop Alzheimer’s later in life
  • If you deprive a healthy adult of sleep or deep sleep for just one night – there’s an immediate increase in beta-amyloid proteins (present in Alzheimer’s)
  • The brain has a cleansing system called the glymphatic system (similar to the body’s lymphatic system) which kicks in during deep sleep
  • The glymphatic system washes away beta-amyloid protein which helps fight Alzheimer’s disease
  • Sleep is a missing piece in the puzzle of aging and Alzheimer’s disease
  • Maybe we can increase mid-life interventions around sleep to prevent the incidence of Alzheimer’s disease
  • “The elastic band of sleep deprivation will stretch only so far before it snaps. If you fight biology, normally you lose.” – Dr. Matthew Walker

Sleep, Sleep Quality & Cardiovascular Disease

  • Daylight saving time: 24% increase of heart attacks in spring and 21% reduction in heart attacks in fall
  • People who consistently get less than 6 hours of sleep have a 200% increased risk of cardiovascular disease or heart attack
  • In studies, people who have no pre-existing record of heart disease but sleeping less than 6 hours per night have a 200-300% increase in calcification of coronary artery
  • During deep sleep, heart rate decelerates and respiratory rate is low – if you are chronically high in heart rate and respiratory rate, blood pressure will be affected in wakefulness
  • During deep sleep we shift from sympathetic nervous system to parasympathetic nervous system in which we rest, heart rate decelerates, respiratory rate decreases
  • Short sleep and fragmented sleep have a high likelihood of hardening blood vessels which can be the pathway to cardiovascular disease and heart attack
  • Sleep is just as critical as other diet and lifestyle factors for cardiovascular health

The Difficulty In Losing Weight On Short Sleep

  • When you are dieting but don’t sleep enough you will lose muscle, gain fat, and crave less nutrient-dense foods
  • Short sleep causes dysfunction in two appetite-regulating hormones leptin and ghrelin
  • Leptin: hormone of satiety which says to brain and body you are full
  • Ghrelin: the hunger hormone that cues you to eat more
  • With lack of sleep, ghrelin increases and leptin drops away so you lose the signal of being full
  • Short sleep is associated with intake of 200-400 extra calories – and consumption of less nutritious foods
  • Emotional, impulsive centers of the brain are revved up so our desires are not in check and we eat a higher rate of processed, sugary foods

Improving Sleep In Mid-Life

  • It’s never too late to improve sleep quality
  • Sleep apnea diagnosis and consistent CPAP use in mid-life staves off the onslaught of Alzheimer’s disease and cognitive decline
  • There is a regenerative capacity in some regions of the brain associated with memory  

Work Quality Of Medical Residence On Short Sleep

  • Medical residency programs in the U.S. are notoriously associated with lack of sleep and 30-hour shifts – even though we know better
  • The physician who invented the residency program schedule turned out to be a cocaine addict who was using cocaine to sustain the long hours
  • Medical residence on a 30-hour shift made 400% more diagnostic errors in the Intensive Care Unit
  • If a surgeon has slept less than 6 hours in the previous 24 hour period, they are 170% more likely to make a major surgical error
  • Rates of suicide are higher among medical residents
  • Some parts of Europe have rules around residency programs and keep work schedules to 16 hours

School Start Times Are Hurting Teens

  • The early school start time has been contested in recent years
  • When school start times are shifted to a later time: academic grades increase, truancy rates decrease, psychological and psychiatric referrals decrease, life expectancy increases (less road traffic accidents)
  • 70% reduction in accident rates involving teens in areas where school start times were later
  • During the adolescent transition, there’s a shift in a biological rhythm where they want to go to bed later and wake up later
  • Asking a teen to wake up at 6 am is like asking an adult to wake up at 3:30 am and be the best version of themselves
  • Teens wake up late on weekends because they are trying to sleep off the debt accrued from the weekday
  • Parent-child incongruency: less than 15% of teens get sufficient sleep but 70% of parents think their teens are getting sufficient sleep  
  • The brain doesn’t stop developing until it’s 25 years old, so sleep is critical for development through these years
  • We make the brain efficient for adulthood in these teen years
  • Adolescents and young teens need 8-11 hours of sleep per night
  • School start time should be 10 am
  • ADHD medications strongly promote staying awake so it may be worth considering the timing of medication in hopes of regulating sleep better

Napping, Biphasic, Polyphasic Sleep

  • Polyphasic (multiple periods of sleep throughout 24 hours) sleep doesn’t work – nothing in our biology suggests we’re designed to have multiple bouts of sleep
  • There is an argument to be made for biphasic sleep where we sleep 6-7 hours at night then siesta a few hours during the day
  • Daily sleepiness from 2-4pm: it’s possible our natural sleep pattern is designed to nap at that period
  • When Greece experimented with eliminating siesta, cardiovascular health decreased so much so that there was between a 30-60% increase in the likelihood of heart attack
  • Naps are a double-edged sword: if you struggle with sleep at night, do not nap during the day in order to build up sleepiness and hopefully sleep at night
  • If you have fragile sleep and insomnia – don’t nap during the day because you’re releasing healthy sleep pressure that’s built up
  • If you don’t have sleep problems, naps before 2 pm are ok
  • Non-pharmacological ways to increase sleep pressure: exercise and control anxiety

Best Practices For Improved Sleep (Barring Insomnia Or Sleep Apnea)

  • We are on the go so much, we don’t reflect on our day until our head hits the pillow – at that point, good sleep will be hard to come by because we are likely to catastrophize
  • Visualize a walk you have taken, a hike, a car racing, etc. – anything you enjoy doing
  • Meditation can decrease the severity of insomnia more effectively than medication
  • Control for better sleep: temperature, regularity, darkness, limit alcohol and caffeine intake, exercise or physical activity often
  • Brain and body need to drop in core temperature to fall asleep and stay asleep – it’s easier to sleep in cold versus heat
  • Hunter-gatherers sleep 1-2 hours after sun goes down and waking with sunrise – this is because of temperature not light as we believed
  • Why do we want hands and feet out of covers? Hands and feet are radiators of heat because they are highly vascular – we are evacuating the heat from our bodies out of limbs to cool down
  • A warm bath or shower can actually help sleep because vasodilation is bringing warmth out and evacuating
  • Go to sleep at the same time and wake up at the same time – even on weekends and if you had a bad night of sleep
  • Regularity anchors sleep and increase quality and quantity of sleep
  • Figure out chronotype and sleep in accordance with that – don’t get sucked in to “rise and grind” culture – it doesn’t work for everyone
  • Technology masks sleepiness because blue light and apps are designed to be stimulating
  • If you want to take the phone in the bedroom, try to establish a rule that you need to be standing while using it
  • You want to associate with bed with only sleep or intimacy: don’t use the bed for eating, working, watching TV
  • Caffeine can damage sleep in two ways: (1) duration of caffeine in the system – caffeine has an 8-hour half-life; (2) decrease quality and quantity of non-REM deep sleep
  • Alcohol is not a sleep aid: (1) alcohol is a sedative but sedation is not sleep; (2) alcohol fragments sleep so you wake up throughout the night; (3) alcohol is a potent suppressor of REM sleep
  • Even a glass of wine with dinner has an impact on sleep
  • Rich Roll sleeps on his roof in a tent with a gravity blanket!

Non-Prescription And Prescription Sleep Aides

  • Darkness triggers the natural release of melatonin: (1) try dimming lights in the house in the evening; (2) avoid blue light
  • Melatonin is an over the counter supplement used as a sleep aide
  • The placebo effect is strong in melatonin but be careful with brands because it is not FDA regulated
  • In the first half of the day, get at least 40 minutes of direct sunlight each morning to feel more alert and regulate the rhythm
  • Melatonin regulates the timing of sleep and should be used to traveling through time zones but not as a daily regulator of sleep
  • Prescription sleep aides have a purpose in acute scenarios such a grievance, trauma – but are only recommended for short term use and in combination with therapy in most cases
  • There are rebound effects of sleeping pills: sleeping quality is worse once your stop
  • It took George Lucas about 30-40 years to amass $2 billion in profit from Star Wars – it took Ambien 24 months

Trends In Sleep And Full Moon

  • Thinking about the origin of the word “lunatic” – it’s related to lunar patterns and the shifts in how people act
  • There is conflicting evidence but on average, people sleep less when there’s a full moon
  • Sleep duration decreases in full moon possibly because of brightness of the moon which can decrease melatonin

Rich Roll Podcast : , , ,
Notes By Maryann

More Notes on these topics

Top Insights and Tactics From

31 Best Podcasts of All Time

FREE when you join over 35,000 subscribers to the
Podcast Notes newsletter

No Thanks