Why We Sleep: Unlocking the Power of Sleep and Dreams

by Matthew Walker

alcohol will often suppress REM sleep, especially during the first half or two-thirds of the night.

Memories remain vulnerable to disruption of sleep (including that from alcohol) even up to three nights after learning, despite two full nights of natural sleep prior.

A bedroom temperature of around 65 degrees Fahrenheit (18.3°C) is a reasonable goal for the sleep of most people, assuming standard bedding and clothing.

You do not fall asleep faster because you are toasty and warm to the core. Instead, the hot bath invites blood to the surface of your skin, giving you that flushed appearance. When you get out of the bath, those dilated blood vessels on the surface quickly help radiate out inner heat, and your core body temperature plummets.

Hot baths prior to bed can also induce 10 to 15 percent more deep NREM sleep in healthy adults.IV

Sleeping pills do not provide natural sleep, can damage health, and increase the risk of life-threatening diseases.

Sleeping pills effectively knock out the higher regions of your brain’s cortex.

Another unpleasant feature of sleeping pills is rebound insomnia.

There was no difference in how soundly the individuals slept.

individuals using prescription sleep medications are significantly more likely to die and to develop cancer than those who do not.

individuals taking sleeping pills were significantly more likely to die across the study periods (usually a handful of years) than those who were not,

Even very occasional users—those defined as taking just eighteen pills per year—were still 3.6 times more likely to die at some point across the assessment window than non-users.

One frequent link with mortality appears to be higher-than-normal rates of infection.

Why, then, do individuals who are taking sleeping pills that purportedly “improve” sleep suffer higher rates of various infections, when the opposite is predicted? It is possible that medication-induced sleep does not provide the same restorative immune benefits as natural sleep.

Another possible concern of death linked to sleeping pill use is an increased risk for fatal car accidents.

Individuals taking sleeping pills were 30 to 40 percent more likely to develop cancer within the two-and-a-half-year period of the study than those who were not.

risks.

there are already numerous and effective behavioral methods for improving your sleep, especially if you are suffering from insomnia.

establish a regular bedtime and wake-up time, even on weekends,

go to bed only when sleepy and avoid sleeping on the couch early/mid-evenings,

never lie awake in bed for a significant time period; rather, get out of bed and do something quiet and relaxing ...

avoid daytime napping if you are having difficulty s...

reduce anxiety-provoking thoughts and worries by learning to mentally ...

remove visible clockfaces from view in the bedroom, preventing clock-watc...

CBT-I consistently helps people fall asleep faster at night, sleep longer, and obtain superior sleep quality by significantly decreasing the amount of time spent awake at night.

For those of us who are not suffering from insomnia or another sleep disorder, there are things we can do to secure a far better night of sleep using what we call good “sleep hygiene” practices, for which a list of twelve key tips can be found at the National Institutes of Health website; also offered in the appendix of this book.

if you can only adhere to one of these each and every day, make it: going to bed and waking up at the same time of day no matter what.

In other words, sleep may have more of an influence on exercise than exercise has on sleep.

Eating a high-carbohydrate, low-fat diet for two days decreases the amount of deep NREM sleep at night, but increases the amount of REM sleep dreaming,

a four-day diet high in sugar and other carbohydrates, but low in fiber, resulted in less deep NREM sleep and more awakenings at night.

As we have learned time and again throughout the course of this book, sleep is not like a credit system or the bank. 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 in full at a later time.

inadequate sleep costs America and Japan $411 billion and $138 billion each year, respectively.

That’s ironic, considering that you can have both, as we have discovered above.

Not really comparable to look at 4-5% increases against the difference between $140k and $80k!

In the mid-1990s, NASA refined the science of sleeping on the job for the benefit of their astronauts. They discovered that naps as short as twenty-six minutes in length still offered a 34 percent improvement in task performance and more than a 50 percent increase in overall alertness.

In the context of interrogation, sleep deprivation is ill designed for the purpose of obtaining accurate, and thus actionable, intelligence. A lack of sleep, even moderate amounts, degrades every mental faculty necessary to obtain valid information, as we have seen.

recent scientific study demonstrating that one night of sleep deprivation will double or even quadruple the likelihood that an otherwise upstanding individual will falsely confess to something they have not done.

the circadian rhythm of teenagers shifts forward dramatically by one to three hours.

REM sleep is what stands between rationality and insanity.

When the Mahtomedi School District of Minnesota pushed their school start time from 7:30 to 8:00 a.m., there was a 60 percent reduction in traffic accidents in drivers sixteen to eighteen years of age.

An added reason for making sleep a top priority in the education and lives of our children concerns the link between sleep deficiency and the epidemic of ADHD

Most people know the name of the common ADHD medications: Adderall and Ritalin.

Amphetamine and methylphenidate are two of the most powerful drugs we know of to prevent sleep and keep the brain of an adult (or a child, in this case) wide awake.

Based on recent surveys and clinical evaluations, we estimate that more than 50 percent of all children with an ADHD diagnosis actually have a sleep disorder,

Why did we ever force doctors to learn their profession in this exhausting, sleepless way? The answer originates with the esteemed physician William Stewart Halsted, MD, who was also a helpless drug addict.

The term “residency” came from Halsted’s belief that doctors must live in the hospital for much of their training, allowing them to be truly committed in their learning of surgical skills and medical knowledge. Fledgling residents had to suffer long, consecutive work shifts, day and night. To Halsted, sleep was a dispensable luxury that detracted from the ability to work and learn. Halsted’s mentality was difficult to argue with, since he himself practiced what he preached, being renowned for a seemingly superhuman ability to stay awake for apparently days on end without any fatigue. But Halsted had a secret that only came to light years after his death, and helped explain both the maniacal structure of his residency program and his ability to forgo sleep. Halsted was a cocaine addict.

Throughout the course of their residency, one in five medical residents will make a sleepless-related medical error that causes significant, liable harm to a patient.

working for more than sixteen consecutive hours without sleep is hazardous for both the patient and resident physician.

Why, then, can several western European countries train their young doctors within the same time frame when they are limited to working no more than forty-eight hours in one week, without continuous long periods of sleeplessness?

Within three to five years, I am quite certain there will be commercially available, affordable devices that track an individual’s sleep and circadian rhythm with high accuracy. When that happens, we can marry these individual sleep trackers with the revolution of in-home networked devices like thermostats and lighting.

we could program a natural circadian lull and rise in temperature across the night that is in harmony with each body’s expectations, rather than the constant nighttime temperature set in most homes and apartments.