📚 Why We Sleep 💤

🌙 Unlock the secrets of sleep in “Why We Sleep” and discover the fascinating science behind sleep. From the truth about caffeine to the mesmerizing world of dreams, delve into the impact of sleep on memory, creativity, and well-being. Unravel the mysteries of circadian rhythms, jet lag, and melatonin, and embrace the quest for a healthier, more vibrant life. 💤✨

About the book

Author:	Matthew Walker
Year of release:	2017
Genre:	Nonfiction, Science, Self-Help, Neuroscience, PersonalDevelopment, Biology, Health, Psychology
Pages:	419
Average WPM:	422
Date Started/Finished:	20-May-2022 to 25-May-2022
Time took:	5.36 Hours

Impressions

What I Liked About It

Is very detailed and gives scientific backings for a lot of the claims mentioned throughout the book

You can read any section of the book individually which is nice if you wanna reread certain sections

How I Discovered It?

A TikTok; Link 🔗.

Who Should Read It?

Who have issues sleeping or find sleep being useless

Who have a bad sleep schedule

Those who don’t know the importance of sleep

Actionable Takeaways

Not getting enough sleep is a lot more harmful than you think

Sleep is supppper important, not getting any basically kills you

We can never “sleep back” that which we have previously lost is one of the most important take-aways of this book

Top Quotes

• Humans can never “sleep back” that which we have previously lost is one of the most important take-homes of this book

• The shorter your sleep, the shorter your life span. The old maxim “I’ll sleep when I’m dead” is therefore unfortunate.

• Caffeine is not a food supplement. Rather, caffeine is the most widely used (and abused) psychoactive stimulant in the world.

• If you feel as though you could fall asleep easily midmorning, you are very likely not getting enough sleep, or the quality of your sleep is insufficient.

• Time isn’t quite time within dreams. It is most often elongated.

• What you are actually experiencing during deep NREM sleep is one of the most coolest displays of neural collaboration that we know of. Through an astonishing act of self-organization, many thousands of brain cells have all decided to unite and “sing,” or fire, in time. “Every time I watch this stunning act of neural synchrony occurring at night in my own research laboratory, I am humbled: sleep is truly an object of awe”.

• Individual parts of the brain that are up to 30% more active during REM sleep than when we are awake! REM sleep has also been called paradoxical sleep: a brain that appears awake, yet a body that is clearly asleep.

• When it comes to information processing, think of Wake State as reception, NREM sleep as reflection, and REM sleep as integration

Summary + Notes

---

Structure of the book:

Part	Section
1	Demystifies sleep
2	Good, the bad, and the deathly of sleep and sleep loss
3	Safe passage from sleep to the fantastical world of dreams scientifically explained.
4	Seats us first at the bedside, explaining numerous sleep disorders, including insomnia.

1: To Sleep . . .

• Routinely sleeping less than 6-7 hours a night demolishes your immune system, more than doubling your risk of cancer.

Prioritize your sleep for a healthier immune system and reduced risk of cancer!

• Inadequate sleep—even moderate reductions for just 1 week—disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic.
• Perhaps you have also noticed a desire to eat more when you’re tired? This is no coincidence. Too little sleep swells concentrations of a hormone that makes you feel hungry while suppressing a companion hormone that otherwise signals food satisfaction. Despite being full, you still want to eat more.
• Worse, should you attempt to diet but don’t get enough sleep while doing so, it is futile, since most of the weight you lose will come from lean body mass, not fat.
• the shorter your sleep, the shorter your life span. The old maxim “I’ll sleep when I’m dead” is therefore unfortunate.
• It is disquieting to learn that vehicular accidents caused by drowsy driving exceed those caused by alcohol and drugs combined.

2: Caffeine, Jet Lag, and Melatonin: Losing and Gaining Control of Your Sleep Rhythm

• There are two main factors that determine when you want to sleep and when you want to be awake.
  1. The first factor; signal beamed out from your internal twenty-four-hour clock located deep within your brain.
  2. The second factor; a chemical substance that builds up in your brain and creates a “sleep pressure.” The longer you’ve been awake, the more that chemical sleep pressure accumulates, and consequentially, the sleepier you feel.
• Circadian rhythm: Your 24-hour rhythm.
• The average duration of a human adult’s endogenous circadian clock runs around 24 hours and 15 minutes in length.
  • Not everyone’s circadian timing is the same
• Unlike morning larks, night owls are frequently incapable of falling asleep early at night, no matter how hard they try and when they are forced to wake up too early, their prefrontal cortex remains in a disabled, “offline” state.

Embrace your natural chronotype and align your sleep schedule accordingly for better rest!

• An adult’s owlness or larkness, also known as their chronotype, is strongly determined by genetics.
  • If you are a night owl, it’s likely that one (or both) of your parents is a night owl.
• Night owls are not owls by choice. They are bound to a delayed schedule by unavoidable DNA hardwiring. It is not their conscious fault, but rather their genetic fate.
• The night owls in the group would not be going to sleep until 1 or 2 a.m., and not waking until 9 or 10 a.m. The morning larks, on the other hand, would have retired for the night at 9 p.m. and woken at 5 a.m.
• Your suprachiasmatic nucleus communicates its repeating signal of night and day to your brain and body using a circulating messenger called melatonin.
• For every day you are in a different time zone, your suprachiasmatic nucleus can only readjust by about one hour.
  • You may have noticed that it feels harder to acclimate to a new time zone when traveling eastward than when flying westward.
  • Scientists have studied airplane cabin crews who frequently fly on long-haul routes and have little chance to recover
    • First, parts of their brains—specifically those related to learning and memory—had physically shrunk, suggesting the destruction of brain cells caused by the biological stress of time-zone travel.
    • Second, their short-term memory was significantly impaired.
• You can, however, artificially mute the sleep signal of adenosine by using a chemical that makes you feel more alert and awake: caffeine.
  • Caffeine is not a food supplement. Rather, caffeine is the most widely used (and abused) psychoactive stimulant in the world.
  • It is the 2nd most traded commodity on the planet, after oil.
• In pharmacology, we use the term “half-life” when discussing a drug’s efficacy.
  • Caffeine has an average half-life of five to seven hours.
• If you feel as though you could fall asleep easily midmorning, you are very likely not getting enough sleep, or the quality of your sleep is insufficient.)
• Can you function optimally without caffeine before noon? If the answer is “no”
  • You are most likely self-medicating your state of chronic sleep deprivation.

3: Defining and Generating Sleep: Time Dilation and What We Learned from a Baby in 1952

• One last temporal distortion deserves mention here—that of time dilation in dreams, beyond sleep itself. Time isn’t quite time within dreams. It is most often elongated.
• Rapid eye movement (REM) sleep, the stage in which humans principally dream.
• Dramatic deceleration of neural time may be the reason we believe our dream life lasts far longer than our alarm clocks otherwise assert.
• Humans don’t just sleep, but cycle through two completely different types of sleep. They named these sleep stages based on their defining ocular features:
  • Non–Rapid Eye Movement, or NREM sleep
  • Rapid Eye Movement, or REM sleep
• Since your brain desires most of its REM sleep in the last part of the night, which is to say the late-morning hours, you will lose 60%-90% of all your REM sleep, even though you are losing 25% of your total sleep time.
• What you are actually experiencing during deep NREM sleep is one of the most epic displays of neural collaboration that we know of. Through an astonishing act of self-organization, many thousands of brain cells have all decided to unite and “sing,” or fire, in time. Every time I watch this stunning act of neural synchrony occurring at night in my own research laboratory, I am humbled: sleep is truly an object of awe.
• Each night, the long-range brainwaves of deep sleep will move memory packets (recent experiences)
  • from a Short-term storage site (which is fragile) -> More permanent, and thus safer, long-term storage location.
• Individual parts of the brain that are up to 30% more active during REM sleep than when we are awake! REM sleep has also been called paradoxical sleep: a brain that appears awake, yet a body that is clearly asleep.
• When it comes to information processing, think of:
  • Wake state principally as reception (experiencing and constantly learning the world around you)
  • NREM sleep as reflection (storing and strengthening those raw ingredients of new facts and skills)
  • REM sleep as integration (interconnecting these raw ingredients with each other, with all past experiences, and, in doing so, building an ever more accurate model of how the world works, including innovative insights and problem-solving abilities).

4: Ape Beds, Dinosaurs, and Napping with Half a Brain: Who Sleeps, How Do We Sleep, and How Much?

• We can pose a very different theory: sleep was the first state of life on this planet, and it was from sleep that wakefulness emerged.
• Humans (and all other species) can never “sleep back” that which we have previously lost is one of the most important take-homes of this book
• About NREM and REM
  • NREM sleep helps transfer and make safe newly learned information into long-term storage sites of the brain.
  • REM sleep takes these freshly minted memories and begins colliding them with the entire back catalog of your life’s autobiography.

5: Changes in Sleep Across the Life Span

• Findings helped explain why rationality is one of the last things to flourish in teenagers, as it is the last brain territory to receive sleep’s maturational treatment.
  • Certainly sleep is not the only factor in the ripening of the brain, but it appears to be a significant one that paves the way to mature thinking and reasoning ability.
• It’s very understandable for parents to feel frustrated in this way, since they believe that their teenager’s sleep patterns reflect a conscious choice and not a biological edict. But non-volitional, non-negotiable, and strongly biological they are
• As parents, we are often too focused on what sleep is taking away from our teenagers, without stopping to think about what it may be adding. Caffeine also comes into question. There was once an education policy in the US known as “No child left behind.” Based on scientific evidence, a new policy has rightly been suggested by my colleague Dr. Mary Carskadon: “No child needs caffeine.”

6: Your Mother and Shakespeare Knew: The Benefits of Sleep for the Brain

• Failed by the lack of public education, most of us do not realize how remarkable a panacea sleep truly is.
• The memory refreshment was related to lighter, stage 2 NREM sleep, and specifically the short, powerful bursts of electrical activity called sleep spindles, noted in chapter 3.
  • The more sleep spindles an individual obtained during the nap, the greater the restoration of their learning when they woke up.
• In contrast, an equivalent time spent awake was deeply hazardous to recently acquired memories, resulting in an accelerated trajectory of forgetting.
• The more deep NREM sleep, the more information an individual remembered the next day.
• Before having slept, participants were fetching memories from the short-term storage site of the hippocampus—that temporary warehouse.
  • Which is a vulnerable place to live for any long duration of time if you are a new memory.
• After the full night of sleep, participants were now retrieving that same information from the neocortex, which sits at the top of the brain—a region that serves as the long-term storage site for fact-based memories, where they can now live safely, perhaps in perpetuity.
• Analogous to looping your favorite songs in a repeating playlist at night, we cherry-pick specific slices of your autobiographical past, and preferentially strengthen them by using the individualized sound cues during sleep.
• You would have the power to write and rewrite your own remembered life narrative or, more concerning, that of someone else
• Practice does not make perfect. It is practice, followed by a night of sleep, that leads to perfection.
• The 100-meter sprint superstar Usain Bolt has, on many occasions, taken naps in the hours before breaking the world record, and before Olympic finals in which he won gold.

Ever wondered how sleep affects memory? Dreams play a crucial role in memory consolidation.

7: Too Extreme for the Guinness Book of World Records: Sleep Deprivation and the Brain

• Risks associated with sleep deprivation are considered to be far, far higher. Unacceptably high, in fact, based on the evidence.
• With chronic sleep restriction over months or years, an individual will actually acclimate to their impaired performance, lower alertness, and reduced energy levels. That low-level exhaustion becomes their accepted norm, or baseline.
• 60 years of scientific research prevent me from accepting anyone who tells me that he or she can “get by on just four or five hours of sleep a night just fine.”
• After 30 years of intensive research, we can now answer many of the questions posed earlier. The recycle rate of a human being is around 16 hours. After 16 hours of being awake, the brain begins to fail. Humans need more than 7 hours of sleep each night to maintain cognitive performance. After 10 days of just 7 hours of sleep, the brain is as dysfunctional as it would be after going without sleep for 24 hours. 3 full nights of recovery sleep (i.e., more nights than a weekend) are insufficient to restore performance back to normal levels after a week of short sleeping. Finally, the human mind cannot accurately sense how sleep-deprived it is when sleep-deprived.

Beware of chronic sleep deprivation! Prioritize at least 7 hours of sleep for optimal cognitive function.

• Power naps may momentarily increase basic concentration under conditions of sleep deprivation, as can caffeine up to a certain dose.
• (Context: study done on Bipolar patients) I find it to be an ethically difficult experiment to appreciate, but the scientists had importantly demonstrated that a lack of sleep is a causal trigger of a psychiatric episode of mania or depression.
• Depression is not, as you may think, just about the excess presence of negative feelings. Major depression has as much to do with absence of positive emotions, a feature described as anhedonia: the inability to gain pleasure from normally pleasurable experiences, such as food, socializing, or sex.
• I will summarize this section by offering a discerning quote on the topic of sleep and emotion by the American entrepreneur E. Joseph Cossman:

  “The best bridge between despair and hope is a good night’s sleep.”

• When we compared the effectiveness of learning between the two groups, the result was clear: there was a 40% deficit in the ability of the sleep-deprived group to cram new facts into the brain (i.e., to make new memories), relative to the group that obtained a full night of sleep. To put that in context, it would be the difference between acing an exam and failing it miserably!
• Wakefulness is low-level brain damage, while sleep is neurological sanitation.
• Parenthetically, and unscientifically, I have always found it curious that Margaret Thatcher and Ronald Reagan—2 heads of state that were very vocal, if not proud, about sleeping only 4 to 5 hours a night—both went on to develop the ruthless disease.

Warning: Chronic sleep deprivation may lead to long-term cognitive dysfunction. Prioritize your sleep for a healthier mind!

8: Cancer, Heart Attacks, and a Shorter Life: Sleep Deprivation and the Body

• I was once fond of saying, “Sleep is the third pillar of good health, alongside diet and exercise.” I have changed my tune. Sleep is more than a pillar; it is the foundation on which the other two health bastions sit.
• The less you sleep, the more you are likely to eat.

Sleeping less than 7 or 8 hours a night will increase your probability of gaining weight, being overweight, or being obese, and significantly increases your likelihood of developing type 2 diabetes.

• Inadequate sleep is the perfect recipe for obesity: greater calorie intake, lower calorie expenditure.
• Based on evidence gathered over the past three decades, the epidemic of insufficient sleep is very likely a key contributor to the epidemic of obesity.
• 2 individuals of the same chronological age would not appear to be of the same biological age on the basis of their telomere health if one was routinely sleeping 5 hours a night while the other was sleeping 7 hours a night. The latter would appear “younger,” while the former would artificially have aged far beyond their calendar years.
• Neglect sleep, and you are deciding to perform a genetic engineering manipulation on yourself each night, tampering with the nucleic alphabet that spells out your daily health story.

9: Routinely Psychotic: REM-Sleep Dreaming

4 main clusters of the brain that spike in activity when someone starts dreaming in REM sleep:

1. The visuospatial regions at the back of the brain, which enable complex visual perception.
2. The motor cortex, which instigates movement.
3. The hippocampus and surrounding regions, which support your autobiographical memory.
4. The deep emotional centers of the brain—the amygdala and the cingulate cortex, a ribbon of tissue that sits above the amygdala and lines the inner surface of your brain—both of which help generate and process emotions. Indeed, these emotional regions of the brain are up to 30% more active in REM sleep compared to when we are awake!

There are some individuals who can not only become aware that they are dreaming, but even control how and what they dream. It is called lucid dreaming.

10: Dreaming as Overnight Therapy

• Dreams, like heat from a lightbulb, may serve no function. Dreams may simply be epiphenomena of no use or consequence. They are merely an unintended by-product of REM sleep.
• It postulated that the process of REM-sleep dreaming accomplishes 2 critical goals:
  1. Sleeping to remember the details of those valuable, salient experiences, integrating them with existing knowledge and putting them into autobiographical perspective, yet
  2. Sleeping to forget, or dissolve, the visceral, painful emotional charge that had previously been wrapped around those memories.
• Your recall of these detailed memories is no longer accompanied by the same degree of emotion that was present at the time of the experience. You have not forgotten the memory, but you have cast off the emotional charge, or at least a significant amount of it. You can accurately relive the memory, but you do not regurgitate the same visceral reaction that was present and imprinted at the time of the episode.
• It was not, therefore, time per se that healed all wounds, but instead it was time spent in dream sleep that was providing emotional convalescence. To sleep, perchance to heal.

11: Dream Creativity and Dream Control

• REM sleep and the act of dreaming have another distinct benefit: intelligent information processing that inspires creativity and promotes problem solving. So much so, that some individuals try controlling this normally non-volitional process and direct their own dream experiences while dreaming.
• No one challenged the evidence that Mendeleev was provided a dream-inspired formulation of the periodic table. It was his dreaming brain, not his waking brain, that was able to perceive an organized arrangement of all known chemical elements. Leave it to REM-sleep dreaming to solve the baffling puzzle of how all constituents of the known universe fit together—an inspired revelation of cosmic magnitude.
• Little wonder, then, that you have never been told to “stay awake on a problem.” Instead, you are instructed to “sleep on it.” Interestingly, this phrase, or something close to it, exists in most languages (from the French dormir sur un problem, to the Swahili kulala juu ya tatizo), indicating that the problem-solving benefit of dream sleep is universal, common across the globe.
• Lucid dreaming occurs at the moment when an individual becomes aware that he or she is dreaming.

12: Things That Go Bump in the Night: Sleep Disorders and Death Caused by No Sleep

• The term “somnambulism” refers to sleep (somnus) disorders that involve some form of movement (ambulation). It encompasses conditions such as sleepwalking, sleep talking, sleep eating, sleep texting, sleep sex, and, very rarely, sleep homicide.
• All these events arise from the deepest stage of non-dreaming (NREM) sleep, and not dream (REM) sleep. If you rouse an individual from a sleepwalking event and ask what was going through their mind, rarely will they report a thing—no dream scenario, no mental experience.
• One explanation of the former is simply the fact that we have greater amounts of deep NREM sleep when we are young, and therefore the statistical likelihood of sleepwalking and sleep talking episodes occurring is higher.
• Many individuals suffer from insomnia, yet some believe they have the disorder when they do not.
• Being sleep deprived is not insomnia.
• In the field of medicine, sleep deprivation is considered as
  1. having the adequate ability to sleep; yet
  2. giving oneself an inadequate opportunity to sleep—that is, sleep-deprived individuals can sleep, if only they would take the appropriate time to do so.
• Insomnia is the opposite:
  1. suffering from an inadequate ability to generate sleep, despite
  2. allowing oneself the adequate opportunity to get sleep. People suffering from insomnia therefore cannot produce sufficient sleep quantity/quality, even though they give themselves enough time to do so (seven to nine hours).
• It is worth noting the condition of sleep-state misperception, also known as paradoxical insomnia. Here, patients will report having slept poorly throughout the night, or even not sleeping at all. However, when these individuals have their sleep monitored objectively using electrodes or other accurate sleep monitoring devices, there is a mismatch. The sleep recordings indicate that the patient has slept far better than they themselves believe, and sometimes indicate that a completely full and healthy night of sleep occurred. Patients suffering from paradoxical insomnia therefore have an illusion, or misperception, of poor sleep that is not actually poor. As a result, such patients are treated as hypochondriacal.
• One distinction separates insomnia into two kinds.
  1. The first is sleep onset insomnia, which is difficulty falling asleep.
  2. The second is sleep maintenance insomnia, or difficulty staying asleep
• Recursive loops of emotional programs, together with retrospective and prospective memory loops, keep playing in the mind, preventing the brain from shutting down and switching into sleep mode.
• Insomnia patients wake up not feeling refreshed. Consequentially, patients are unable to function well during the day, cognitively and/or emotionally. In this way, insomnia is really a 24/7 disorder: as much a disorder of the day as of the night.
• Medically, narcolepsy is considered to be a neurological disorder, meaning that its origins are within the central nervous system, specifically the brain. The condition usually emerges between ages 10 and 20 years. There is some genetic basis to narcolepsy, but it is not inherited.
• There are at least three core symptoms that make up the disorder:
  1. Excessive daytime sleepiness
  2. Sleep paralysis
  3. Cataplexy
• Don’t worry if you have had an episode of sleep paralysis at some point in your life. It is not unique to narcolepsy. Around 1 in 4 healthy individuals will experience sleep paralysis, which is to say that it is as common as hiccups.
• If you saw a patient collapse under the influence of cataplexy, you would be convinced that they had fallen completely unconscious or into a powerful sleep. This is untrue. Patients are awake and continue to perceive the outside world around them.
• That switch—the sleep-wake switch—is located just below the thalamus in the center of the brain, in a region called the hypothalamus. It is the same neighborhood that houses the 24-hour master biological clock, perhaps unsurprisingly.

13: iPads, Factory Whistles, and Nightcaps: What’s Stopping You from Sleeping?

5 key factors have powerfully changed how much and how well we sleep:

1. Constant electric light as well as LED light
2. Regularized temperature
3. Caffeine (discussed in chapter 2)
4. Alcohol
5. A legacy of punching time cards

Despite being just 1-2% of the strength of daylight, this ambient level of incandescent home lighting can have 50% of the melatonin-suppressing influence within the brain.

Create a sleep-friendly environment! Minimize ambient light for better melatonin production and sleep quality.

• Blue LED lights offer considerable advantages over incandescent lamps in terms of lower energy demands and, for the lights themselves, longer life spans. But they may be inadvertently shortening our own.
• Evening blue LED light has twice the harmful impact on nighttime melatonin suppression than the warm, yellow light from old incandescent bulbs, even when their lux intensities are matched.

I am very deliberately avoiding the term “sleep,” however, because sedation is not sleep. Alcohol sedates you out of wakefulness, but it does not induce natural sleep. The electrical brainwave state you enter via alcohol is not that of natural sleep; rather, it is akin to a light form of anesthesia.

• First, alcohol fragments sleep, littering the night with brief awakenings. Alcohol-infused sleep is therefore not continuous and, as a result, not restorative.
• Second, alcohol is one of the most powerful suppressors of REM sleep that we know of.

Brain’s non-negotiable requirement for sleep the first night after learning for the purposes of memory processing.

• You will always find it easier to fall asleep in a room that is too cold than too hot , since a room that is too cold is at least dragging your brain and body in the correct (downward) temperature direction for sleep.
• Your nocturnal melatonin levels are therefore controlled not only by the loss of daylight at dusk, but also the drop in temperature that coincides with the setting sun.

Your body is not passive in letting the cool of night lull it into sleep, but actively participates. One way you control your core body temperature is using the surface of your skin. Most of the thermic work is performed by 3 parts of your body in particular:

1. Your hands
2. Your feet
3. Your head

Wendell Berry, VII modern society has taken one of nature’s perfect solutions (sleep) and neatly divided it into two problems:

1. a lack thereof at night, resulting in
2. an inability to remain fully awake during the day.

14: Hurting and Helping Your Sleep: Pills vs. Therapy

• The older sleep medications—termed “sedative hypnotics,” such as diazepam—were blunt instruments. They sedated you rather than assisting you into sleep. Understandably, many people mistake the former for the latter.
• The obvious methods involve reducing caffeine and alcohol intake, removing screen technology from the bedroom, and having a cool bedroom. In addition, patients must
  1. establish a regular bedtime and wake-up time, even on weekends,
  2. go to bed only when sleepy and avoid sleeping on the couch early/mid-evenings,
  3. never lie awake in bed for a significant time period; rather, get out of bed and do something quiet and relaxing until the urge to sleep returns,
  4. avoid daytime napping if you are having difficulty sleeping at night,
  5. reduce anxiety-provoking thoughts and worries by learning to mentally decelerate before bed, and
  6. remove visible clock faces from view in the bedroom, preventing clock-watching anxiety at night.
• Sleep and physical exertion have a bidirectional relationship. Many of us know of the deep, sound sleep we often experience after sustained physical activity
• Sleep, in return, will boost your fitness and energy, setting in motion a positive, self-sustaining cycle of improved physical activity (and mental health).
• Try not to exercise right before bed. Body temperature can remain high for an hour or two after physical exertion.

15: Sleep and Society: What Medicine and Education Are Doing Wrong; What Google and NASA Are Doing Right

Taken as a whole, 1 out of every 2 adults across all developed countries (approximately 800 million people) will not get the necessary sleep they need this coming week.

Sleep matters in society! Explore the societal impact of insufficient sleep and its consequences.

The brain can never recover all the sleep it has been deprived of. We cannot accumulate a debt without penalty, nor can we repay that sleep debt at a later time.

I offer 4 diverse yet clear examples of how insufficient sleep is impacting the fabric of human society:

• sleep in the workplace,
• torture (yes, torture…),
• sleep in the education system,
• sleep in medicine and health care.

SLEEP IN THE WORKPLACE

People often tell me that they do not have enough time to sleep because they have so much work to do. Without wanting to be combative in any way whatsoever, I respond by informing them that perhaps the reason they still have so much to do at the end of the day is precisely because they do not get enough sleep at night.

Ounces of sleep offer pounds of business in return.

SLEEP AND EDUCATION

• Unnecessarily bankrupting the sleep of a teenager could make all the difference in the precarious tipping point between psychological wellness and lifelong psychiatric illness.
• REM sleep is what stands between rationality and insanity.
• It is clear that a tired, under-slept brain is little more than a leaky memory sieve, in no state to receive, absorb, or efficiently retain an education.

SLEEP AND HEALTH CARE

The next time you see a doctor in a hospital, keep in mind the study we have previously discussed, showing that after twenty-two hours without sleep, human performance is impaired to the same level as that of someone who is legally drunk.

16: A New Vision for Sleep in the Twenty-First Century

• The intrusion of technology into our homes and bedrooms is claimed by many of my research colleagues to be robbing us of precious sleep, and I agree.
• The second passive solution concerns electric light. Many of us suffer from overexposure to nighttime light, particularly blue-dominant LED light from our digital devices. This evening digital light suppresses melatonin and delays our sleep timing.
• One practice known to convert a healthy new habit into a permanent way of life is exposure to your own data.
• your “sleep credit score” would be calculated based on a combination of sleep amount and night-to-night sleep continuity.

Appendix: Twelve Tips for Healthy Sleep

Twelve Tips for Healthy Sleep

1. Stick to a sleep schedule
2. Exercise is great, but not too late in the day.
3. Avoid caffeine and nicotine.
4. Avoid alcoholic drinks before bed.
5. Avoid large meals and beverages late at night.
6. If possible, avoid medicines that delay or disrupt your sleep.
7. Don’t take naps after 3 p.m. Naps can help make up for lost sleep, but late afternoon naps can make it harder to fall asleep at night.
8. Relax before bed. Don’t overschedule your day so that no time is left for unwinding.
9. Take a hot bath before bed. The drop in body temperature after getting out of the bath may help you feel sleepy, and the bath can help you relax and slow down so you’re more ready to sleep.
10. Dark bedroom, cool bedroom, gadget-free bedroom. Get rid of anything in your bedroom that might distract you from sleep, such as noises, bright lights, an uncomfortable bed, or warm temperatures.
11. Have the right sunlight exposure.
12. Don’t lie in bed awake. If you find yourself still awake after staying in bed for more than twenty minutes or if you are starting to feel anxious or worried, get up and do some relaxing activity until you feel sleepy.