Why We Sleep: Unlocking the Power of Sleep and Dreams

by Matthew Walker

In the field of medicine, sleep deprivation is considered as (i) having the adequate ability to sleep; yet (ii) 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: (i) suffering from an inadequate ability to generate good sleep quality or quantity, despite (ii) 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).

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.

Without belaboring the point, insomnia is one of the most pressing and prevalent medical issues facing modern society, yet few speak of it this way, recognize the burden, or feel there is a need to act.

Since psychological distress is a principal instigator of insomnia, researchers have focused on examining the biological causes that underlie emotional turmoil. One common culprit has become clear: an overactive sympathetic nervous system, which, as we have discussed in previous chapters, is the body’s aggravating fight-or-flight mechanism.

Based on the results of brain-imaging studies, an analogous problem is occurring in insomnia patients. 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.

Patients with insomnia have a lower quality of sleep, reflected in shallower, less powerful electrical brainwaves during deep NREM. They also have more fragmented REM sleep, peppered by brief awakenings that they are not always aware of, yet still cause a degraded quality of dream sleep.

Emotions make us do things, as the name suggests (remove the first letter from the word).

There are at least three core symptoms that make up the disorder: (1) excessive daytime sleepiness, (2) sleep paralysis, and (3) cataplexy.

That switch—the sleep-wake switch—is located just below the thalamus in the center of the brain, in a region called the hypothalamus.

To do this, the sleep-wake switch in the hypothalamus releases a neurotransmitter called orexin.

Scientists have examined the brains of narcoleptic patients in painstaking detail after they have passed away. During these postmortem investigations, they discovered a loss of almost 90 percent of all the cells that produce orexin.

FATAL FAMILIAL INSOMNIA

The underlying cause of FFI is increasingly well understood, and builds on much of what we have discussed regarding the normal mechanisms of sleep generation. The culprit is an anomaly of a gene called PrNP, which stands for prion protein.

One region that this malfeasant protein attacks, and attacks comprehensively, is the thalamus—that sensory gate within the brain that must close shut for wakefulness to end and sleep to begin.

The problem is that some people confuse time slept with sleep opportunity time.

Epidemiological evidence suggests that the relationship between sleep and mortality risk is not linear, such that the more and more sleep you get, the lower and lower your death risk (and vice versa). Rather, there is an upward hook in death risk once the average sleep amount passes nine hours.

Sleep, like food, water, and oxygen, may share this relationship with mortality risk when taken to extremes.

the suprachiasmatic nucleus—the master twenty-four-hour clock of the brain—the

The loss of daylight informs our suprachiasmatic nucleus that nighttime is now in session; time to release the brake pedal on our pineal gland, allowing it to unleash vast quantities of melatonin that signal to our brains and bodies that darkness has arrived and it is time for bed.

blue LED light has a more harmful impact on human nighttime melatonin suppression than the warm, yellow light from old incandescent bulbs, even when their lux intensities are matched.

Compared to reading a printed book, reading on an iPad suppressed melatonin release by over 50 percent at night. Indeed, iPad reading delayed the rise of melatonin by up to three hours, relative to the natural rise in these same individuals when reading a printed book.

your increased sociability is caused by sedation of one part of your brain, the prefrontal cortex, early in the timeline of alcohol’s creeping effects. As we have discussed, this frontal lobe region of the human brain helps control our impulses and restrains our behavior. Alcohol immobilizes that part of our brain first. As a result, we “loosen up,” becoming less controlled and more extroverted.

First, alcohol fragments sleep, littering the night with brief awakenings.

most of these nighttime awakenings go unnoticed by the sleeper since they don’t remember them.

Second, alcohol will often suppress REM sleep, especially during the first half or two-thirds of the night. When the body metabolizes alcohol it produces by-product chemicals called aldehydes and ketones. The aldehydes in particular will block the brain’s ability to generate REM sleep.

People consuming even moderate amounts of alcohol in the afternoon and/or evening can inadvertently deprive themselves of dream sleep.

In contrast, those who had their sleep laced with alcohol on the first night after learning suffered what can conservatively be described as partial amnesia seven days later, forgetting more than 50 percent of all that original knowledge. This fits well with evidence we discussed earlier: that of the brain’s non-negotiable requirement for sleep the first night after learning for the purposes of memory processing.

go to the pub for a drink in the morning. That way, the alcohol will be out of your system before sleep.

Nightly alcohol will likely disrupt your sleep, and the annoying advice of abstinence is the best, and most honest, I can offer.

To successfully initiate and maintain sleep into the night, as described in chapter 2, your core temperature needs to decrease by 2 to 3 degrees Fahrenheit, or about 1 degree Celsius.

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.

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.

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

Waking up at the same time of day, every day, no matter if it is the week or weekend is a good recommendation for maintaining a stable sleep schedule if you are having difficulty with sleep.

Ambien-laced sleep became a memory eraser, rather than engraver.

There are now more than fifteen such studies from different groups around the world showing higher rates of mortality in those who use sleeping pills.

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 clockfaces from view in the bedroom, preventing clock-watching anxiety at night.

going to bed and waking up at the same time of day no matter what. It is perhaps the single most effective way of helping improve your sleep, even though it involves the use of an alarm clock.

exercise frequently increases total sleep time, especially deep NREM sleep. It also deepens the quality of sleep, resulting in more powerful electrical brainwave activity.

sleep may have more of an influence on exercise than exercise has on sleep.

try not to exercise right before bed. Body temperature can remain high for an hour or two after physical exertion.

sleep is not like a credit system or the bank. The brain can never recover all the sleep it has been deprived of.

Studies in the workplace have found that employees who sleep six hours or less are significantly more deviant and more likely to lie the following day than those who sleep six hours or more.

REM sleep is what stands between rationality and insanity.

Research findings have also revealed that increasing sleep by way of delayed school start times wonderfully increases class attendance, reduces behavioral and psychological problems, and decreases substance and alcohol use.

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. That is the very last thing that such a child needs.