#221 ‒ Understanding sleep and how to improve it
This episode features sleep expert Dr. Matthew Walker, discussing the evolutionary importance and stages of sleep, chronotypes, and practical tips for improving sleep. He covers napping, hygiene, optimal temperature, blue light, caffeine, and the dangers of sleeping pills, advocating for alternatives like CBTI.
Deep Dive Analysis
10 Topic Outline
Evolutionary Importance and Paradox of Sleep
Understanding the Stages of Sleep and Brainwave Activity
Sleep Chronotypes: Genetic Basis and Life-Stage Changes
Defining Sleep Efficiency and Addressing Insomnia
The Pros and Cons of Napping
Essential Sleep Hygiene and Wind-Down Routines
Optimizing Room Temperature for Better Sleep
Revisiting Blue Light's Impact on Sleep
Caffeine: Health Benefits, Timing, and Antioxidant Considerations
Dangers of Sleeping Pills and Effective Alternatives like CBTI
10 Key Concepts
Sleep as a Foundation of Health
Matt Walker argues that sleep is not merely a third pillar but the foundational support for diet and exercise, crucial for overall health and de-risking various diseases. It is considered the greatest life support system and health insurance policy.
Non-Rapid Eye Movement (Non-REM) Sleep
One of two main sleep stages, subdivided into four stages (1-4) of increasing depth. Stages 3 and 4 are deep, restorative sleep characterized by slow, high-amplitude brainwaves, crucial for information transfer within the brain.
Rapid Eye Movement (REM) Sleep
The other main sleep stage, named for rapid eye movements. It is a phase of irrational, hallucinogenic consciousness, and its proportion increases in the latter half of the night, making it vulnerable to shortchanging with early waking.
Sleep Cycle Architecture (Hypnogram)
The standard 90-minute cycling pattern between non-REM and REM sleep throughout the night. The ratio of non-REM to REM changes, with more deep non-REM sleep in the first half and more REM sleep in the second half.
Sleep Chronotype
An individual's innate predisposition to be a morning person, an evening person, or somewhere in between, influenced by genetics and changing across the lifespan. It determines when the peak and trough of one's circadian rhythm arrive on the 24-hour clock face.
Sleep Efficiency
The percentage of time spent actually asleep while in bed. It's crucial to distinguish between total time in bed and actual sleep duration, as low efficiency means less restorative sleep even with ample opportunity.
Sleep Pressure (Adenosine)
A physiological drive for sleep that builds up the longer one is awake. Napping can reduce this pressure, making it harder to fall asleep at night, akin to opening a valve on a pressure cooker.
Cognitive Behavioral Therapy for Insomnia (CBTI)
A non-pharmacological, psychological method considered the first-line treatment for insomnia. It involves working with a therapist to understand and modify behaviors and thoughts that interfere with sleep, creating a bespoke solution for the individual.
Biphasic Sleep
A sleep pattern involving two bouts of sleep within a 24-hour period, often seen in hunter-gatherer tribes. This typically includes a shorter afternoon nap in addition to nighttime sleep, differing from the monophasic sleep common in modern society.
Cognitive Arousal vs. Blue Light Effect
Matt Walker's updated understanding that technology disrupts sleep less due to blue light emission and more due to its mentally stimulating and activating nature. These devices create a competing force that masks natural sleepiness, rather than solely impacting melatonin release.
15 Questions Answered
Evolution designed humans to spend a third of their lives sleeping, despite the vulnerability and missed opportunities for foraging or mating, indicating sleep serves absolutely vital functions for survival and health.
Sleep progresses through non-REM stages (1-4) and REM sleep. Wakefulness has fast, low-amplitude brainwaves; non-REM stages show alpha, theta, and then slow, high-amplitude delta waves (deep sleep), while REM sleep involves rapid eye movements and a more active brain state.
Humans cycle through non-REM and REM sleep approximately every 90 minutes. The first half of the night is rich in deep non-REM sleep, while the second half is predominantly characterized by REM sleep.
A sleep chronotype describes whether an individual is a morning person, evening person, or in between, largely determined by a combination of about nine 'clock genes' that control the timing of one's circadian rhythm.
Chronotypes shift from being more morning-oriented in childhood, to later (evening-oriented) in adolescence, then shuttling back in adulthood, and regressing to an earlier type in older age.
Understanding your chronotype can explain struggles with early schedules, alleviate feelings of culpability for being a 'night owl,' and help in aligning one's work/life schedule with natural biology to improve sleep and overall well-being.
Sleep efficiency is the percentage of time spent actually sleeping while in bed. It's crucial to distinguish between total time in bed and actual sleep duration, as low efficiency means less restorative sleep even with ample opportunity.
Naps can provide learning and memory benefits, even short ones. However, if one struggles with nighttime sleep, naps are detrimental as they reduce sleep pressure, making it harder to fall asleep later. If nighttime sleep is good, naps can be fine.
The optimal room temperature for most people is around 65 to 67 degrees Fahrenheit. A cooler environment facilitates the necessary drop in core body temperature for good sleep.
To fall asleep, the core body temperature needs to drop, which can be aided by warming the extremities (like feet/hands) to radiate heat. Maintaining a cool ambient temperature helps stay asleep, and a slight warm-up can aid waking.
While blue light can delay melatonin release, Matt Walker has shifted his view to emphasize that the primary disruption from evening technology use comes from the cognitive activation and mental stimulation these devices induce, which masks natural sleepiness.
Caffeine can disrupt sleep quality, even when consumed in the morning, due to genetic differences in metabolism. However, low to moderate coffee consumption is associated with de-risking various diseases, possibly due to the antioxidant content of the coffee bean itself.
Sedative hypnotics carry increased risks of death, cancer, and weakened immune function, with mortality risk increasing even with infrequent use. They also do not produce natural sleep and can lead to worse sleep (sleep rebound insomnia) upon cessation.
The American College of Physicians recommends Cognitive Behavioral Therapy for Insomnia (CBTI) as the first-line treatment due to its efficacy, lasting benefits, and lack of health risks associated with pharmacological interventions.
Benzodiazepines (like Ativan, Xanax, Valium) carry statistically significant mortality risks even with infrequent use and do not produce natural sleep. GHB/Xyrem may increase 'scored' deep sleep but alters the electrical signature of sleep, notably decreasing sleep spindles critical for memory and brain plasticity.
22 Actionable Insights
1. Prioritize Sleep as Health Foundation
Recognize sleep as the fundamental pillar of good health, even more critical than diet or exercise, as its deprivation leads to the quickest reduction in overall health.
2. Understand Sleep Efficiency & Opportunity
Aim for 8 to 9 hours of ‘sleep opportunity’ (time in bed) to achieve 7 to 8 hours of actual sleep, accounting for typical inefficiencies where 10-15% of time in bed is spent awake. Utilize sleep trackers to monitor total sleep time and efficiency, not just time in bed.
3. Establish Sleep Regularity
Maintain a consistent sleep schedule by going to bed and waking up at the same time every day, as regularity is crucial for optimal sleep.
4. Optimize Bedroom Temperature
Keep your bedroom cool, ideally between 65-67 degrees Fahrenheit, as a cooler environment facilitates falling asleep and maintaining deep sleep throughout the night.
5. Implement a Wind Down Routine
Create a consistent 15-30 minute pre-sleep routine involving relaxing activities like light stretches or meditation, and put away all phones and gadgets to allow your brain to gradually transition into sleep.
6. Avoid Staying in Bed Awake
If you find yourself awake for more than 20 minutes, get out of bed and engage in a non-stimulating activity, returning to bed only when you feel sleepy, to prevent your brain from associating the bed with wakefulness.
7. Manage Napping Wisely
If you struggle with sleep at night, avoid daytime naps to build sufficient ‘sleep pressure’ for deeper nighttime sleep. However, if you sleep well at night, short naps (e.g., 17 minutes) can be beneficial.
8. Limit Evening Alcohol & Caffeine
Avoid alcohol and caffeine, especially in the afternoon and evening, as they can significantly disrupt sleep architecture and quality.
9. Ensure Darkness & Daylight Exposure
Maximize darkness in your sleeping environment at night and ensure you get ample daylight exposure during the first half of the day to properly regulate your circadian rhythm.
10. Keep Technology Out of Bedroom
Store all technological devices outside the bedroom to prevent mental stimulation, ‘sleep procrastination,’ and the anticipatory anxiety associated with checking them.
11. Delay Morning Phone Check
Avoid checking your phone immediately upon waking to prevent a ’tsunami’ of anxiety and information overload, which can lighten sleep throughout the night due to anticipatory stress. Start with a 5-10 minute delay and gradually increase.
12. Remove Bedroom Clocks
If you struggle with sleep, remove all visible clocks from your bedroom to reduce anxiety about the time and the inability to fall asleep.
13. Understand Your Sleep Chronotype
Determine your innate chronotype (morning, evening, or in-between) using tools like the MEQ test to understand your natural sleep-wake timing, which can explain struggles and help align your schedule with your biology.
14. Seek Professional Help for Sleep Disorders
If sleep hygiene tips are ineffective, consult a doctor to rule out and treat underlying sleep disorders like insomnia or sleep apnea, as these conditions require specific medical intervention.
15. Prioritize CBTI for Insomnia
For insomnia, pursue Cognitive Behavioral Therapy for Insomnia (CBTI) as the first-line treatment, as it is a non-pharmacological, psychological method that is as efficacious as sleeping pills in the short term and offers lasting benefits.
16. Avoid Sedative Hypnotic Sleeping Pills
Strongly avoid sedative-hypnotic sleeping pills (e.g., Ambien, Lunesta) due to significant health risks, including increased mortality, weakened immune function, and nominal benefits over placebo. Use only as a very last resort under strict medical guidance.
17. Avoid Benadryl/OTC Sleep Aids
Shy away from using over-the-counter sleep aids like Benadryl or Advil PM, as they carry statistically significant risks similar to prescription sleeping pills.
18. Re-evaluate Blue Light’s Primary Impact
Recognize that the detrimental effect of technology on sleep is primarily due to its mentally stimulating and activating nature, rather than solely the blue light emitted from screens.
19. Moderate Morning Caffeine Consumption
Moderate caffeine consumption (1-2 cups) in the morning is generally acceptable and may offer health benefits, possibly due to the antioxidant content of coffee beans, but be mindful of individual sensitivity and timing.
20. Consider Decaffeinated Coffee for Antioxidants
If concerned about caffeine’s impact on sleep, opt for decaffeinated coffee, which still provides beneficial antioxidants without the stimulating effects.
21. Benzodiazepines for Extreme Jet Lag (Last Resort)
For extreme jet lag (e.g., 12-hour time zone difference), benzodiazepines (like Valium) can be considered as a very infrequent, last-resort measure to induce sleep, but be aware that even infrequent use carries a statistically significant increase in mortality risk.
22. Do Not Use Xyrem/GHB for Sleep Optimization
Avoid using Xyrem or GHB to optimize sleep, as it does not produce naturalistic sleep and can decrease critical sleep spindle activity essential for learning and memory, making it suitable only for specific medical conditions like narcolepsy.
5 Key Quotes
If sleep doesn't serve an absolutely vital set of functions, it's the biggest mistake that the evolutionary process has ever made.
Matt Walker
Sleep is the foundation on which those two other things sit. It's not the third pillar of good health. I think it is the foundation.
Matt Walker
I would rather you stick your genitals in a grinder than you take Ambien or Lunesta.
Peter Attia
When you fight biology, you normally lose. And the way you know you've lost is often through disease and sickness.
Matt Walker
Sleep is much more like trying to land a plane. It takes time to gradually descend down onto that hard foundation of this thing that we call a stable night of sleep.
Matt Walker
4 Protocols
Insomnia Treatment (Sleep Restriction Therapy)
Matt Walker- Constrain sleep opportunity (total time allowed in bed) down to approximately six hours.
- Build up more sleep pressure by being awake longer during the day.
- Force the brain to realize it has a limited opportunity for sleep, preventing it from having luxury time to be awake in bed.
- Brute force efficiency, causing the brain to get its sleep within the constrained window, leading to markedly increased efficiency.
General Sleep Hygiene Tips
Matt Walker- Maintain regularity: Go to bed and wake up at the same time every day.
- Ensure lots of darkness at night and get plenty of daylight during the first half of the day.
- Keep the bedroom cool, ideally around 65-67 degrees Fahrenheit.
- If you've been awake in bed for 20 minutes, get up, go do something else, and only return to bed when you feel sleepy.
- Avoid alcohol and caffeine in the afternoon and evenings.
Wind-Down Routine for Better Sleep
Matt Walker- Give yourself a dedicated wind-down opportunity time, typically 15-30 minutes, before bed.
- Engage in calming activities such as light stretches or meditation.
- Put all phones and gadgets away, and stay clear of any inbound communications in the last 30 minutes before sleep.
- Maintain consistency with your chosen routine, as breaking it can negatively impact sleep.
Technology Avoidance in the Bedroom (Advanced)
Matt Walker- Remove all clock faces from your bedroom to prevent anxiety about the time if you struggle to fall asleep.
- Keep all technology (phones, iPads, etc.) outside of the bedroom.
- Avoid checking your phone as the first thing you do in the morning to prevent a flood of anticipatory anxiety.
- If you must have your phone in the bedroom, use it only while standing up; once you want to sit or lie down, put the phone away.
- Set manageable, incremental goals for reducing phone use around sleep times, starting with small durations and gradually extending them.