Top Quotes: “Why We Sleep” — Matthew Walker
Introduction
“Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer. Insufficient sleep is a key lifestyle factor determining whether or not you’ll develop Alzheimer’s disease. Inadequate sleep — even moderate reductions for just one week — disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic. Short sleeping increases the likelihood of your coronary arteries becoming blocked and brittle, setting you on a path toward cardiovascular disease, stroke, and congestive heart failure. Sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety, and suicidality.
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. It’s a proven recipe for weight gain in sleep-deficient adults and children alike. Worse, should you attempt to diet but don’t get enough sleep while doing so, it’s futile, since most of the weight you lose will come from lean body mass, not fat.
Add the above health consequences up, and a proven link becomes easier to accept: the shorter your sleep, the shorter your lifespan. The old maxim ‘I’ll sleep when I’m dead’ is therefore unfortunate. Adopt this mindset and you’ll be dead sooner and the quality of that (shorter) life will be worse. The elastic band of sleep deprivation can stretch only so far before it snaps. Sadly, human beings are in fact the only species that will deliberately derive themselves of sleep without legitimate gain.”
REM vs. NREM Sleep
“We have no scientific consensus as to why our sleep (and that of all other mammals and birds) cycles in this repeatable but dramatically asymmetrical pattern, though a number of theories exist. One theory I’ve offered is that the uneven back-and-forth interplay between NREM and REM sleep is necessary to elegantly remodel and update our neural circuits at night, and in doing so manage the finite storage space within the brain. Forced by the known storage capacity imposed by a set number of neurons and connections within their memory structures, our brains must find the ‘sweet spot’ between retention of old information and leaving sufficient room for the new. Balancing this storage equation requires identifying which memories are fresh and salient, and which memories that currently exist are overlapping, redundant, or simply no longer relevant.
A key function of deep NREM sleep, which predominates early in the night, is to do the work of weeding out and removing unnecessary neural connections. In contrast, the dreaming stage of REM sleep, which prevails later in the night, plays a role in strengthening those connections.
Combine these two, and we have at least one parsimonious explanation for why the two types of sleep cycle across the night, and why those cycles are initially dominated by NREM sleep early on, with REM sleep reigning supreme in the second half of the night. Consider the creation of a piece of sculpture from a block of clay. It starts with placing a large amount of raw materials onto a pedestal (that entire mass of stored autobiographical memories, new and old, offered up to sleep each night). Next comes an initial and extensive removal of superfluous matter (those long stretches of NREM sleep), after which brief intensification of early details can be made (short REM periods). Following this first session, the culling hands return for a second round of deep excavation (another long NREM-sleep phase), followed by a little more enhancing of some fine-grained sculptures that have emerged (slightly more REM sleep). After several more cycles of work, the balance of sculptural need has shifted. All core features have been hewn from the original mass of raw material. With only the important clay remaining, the work of the sculptor, and the tools required, must shift toward the goal of strengthening the elements and enhancing features of that which remains (a dominant need for the skills of REM sleep, and little work remaining for NREM sleep).
In this way, sleep may elegantly manage and solve our memory storage crisis, with the general excavatory force of NREM sleep dominating early, after which the etching hand of REM sleep blends, interconnects, and adds details. Since life’s experience is ever-changing, demanding that our memory catalog be updated ad infinitum, our autobiographical sculpture of stored experience is never complete. As a result, the brain always requires a new bout of sleep and its varied stages each night so as to auto-update our memory networks based on the events of the prior day.”
“Have you ever taken a long road trip and noticed that at some point in the journey the FM radio stations you’ve been listening to begin dropping out in signal strength? In contrast, AM stations remain solid. The explanation lies in the radio waves themselves, including the two different speeds of FM and AM transmissions. FM uses faster-frequency radio waves that go up and down many more times per second than AM waves. One advantage of FM waves is that they can carry higher, richer loads of info, and hence they sound better. But there’s a big disadvantage: FM waves run out of steam quickly. AM broadcasts employ a much slower (longer) radio wave. While AM radio waves cannot match the dynamic quality of FM radio, the pedestrian pace of AM waves give them the ability to cover vast distances with less fade. Longer-range broadcasts are therefore possible with the slow waves of AM radio, allowing far-reaching communication between very distant locations.”
“As your brain shifts from the fast-frequency activity of waking to the slower, more measured pattern of deep NREM sleep, the very same long-range communication becomes possible. The steady, slow, communication waves that sweep across the brain during deep sleep open up communication possibilities between distant regions of the brain, allowing them to collaboratively send and receive their different repositories of stored experience.
In this regard, you can think of each individual slow wave of NREM sleep as a courier, able to carry packets of info between different anatomical brain centers. One benefit of these traveling deep-sleep brainwaves is a file transfer process. Each night, the long-range brainwaves of deep sleep will move memory packets (recent experience) from a short-term storage site, which is fragile, to a more permanent, and thus safer, long-term storage location.”
“As is the case when you are awake, the sensory gate of the thalamus once again swings open during REM sleep. But the nature of the gate is different. It is not sensations from the outside that are allowed to journey to the cortex during REM sleep. Rather, signals of emotions, motivations, and memories (past and present) are all played out on the big screens of our visual, auditory, and kinesthetic sensory cortices in the brain. Each and every night, REM sleep ushers you into a preposterous theater wherein you are treated to a bizarre, highly associative carnival of autobiographical themes. When it comes to info processing, think of the 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), and REM sleep as integration (interconnecting those 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).”
“Why did evolution decide to outlaw muscle activity during REM sleep? Because by eliminating muscle activity you’re prevented from acting out your dream experience. During REM sleep, there’s a nonstop barrage of motor commands swirling around the brain, and they underlie the movement-rich experience of dreams. Wise, then, of Mother Nature to have tailored a physiological straitjacket that forbids these fictional movements from becoming reality, especially considering that you’ve stopped consciously perceiving your surroundings. You can well imagine the calamitous upshot of falsely enacting a dream fight, or a frantic sprint from an approaching dream foe, while your eyes are closed and you have no comprehension of the world around you. It wouldn’t take long before you quickly left the gene pool. The brain paralyzes the body so the mind can dream safely.”
The Evolution of Sleep
“Without exception, every animal species studied to date sleeps, or engages in something remarkably like it. This includes insects, such as flies, bees, cockroaches, and scorpions; fish, from small perch to the largest sharks; amphibians, such as frogs; and reptiles, such as turtles, Komodo dragons, and chameleons. All have bona fide sleep. Ascend the evolutionary ladder further and we find that all types of birds and mammals sleep: from shrews to parrots, kangaroos, polar bears, bats, and, of course, we humans. Sleep is universal.
Even invertebrates, such as primordial mollusks and echinoderms, enjoy periods of slumber. In these phases, affectionately termed ‘lethargus,’ they, like humans, become unresponsive to external stimuli. And just as we fall asleep faster and sleep more soundly when sleep-deprived, so, too, do worms, defined by their degree of insensitivity to prods by experimenters.
How ‘old’ does this make sleep? Worms emerged during the Cambrian explosion: at least 500 million years ago. That is, worms (and sleep by association) predate all vertebrate life. This includes dinosaurs, which, by inference, are likely to have slept. Imagine diplodocuses and triceratopses all comfortably settling in for a night of full repose!
Regress evolutionary time still further and we have discovered that the very simplest forms of unicellular organisms that survive for periods exceeding 24 hours, such as bacteria, have active and passive phases that correspond to the light-dark cycle of our planet. It is a pattern that we now believe to be the precursor of our own circadian rhythm, and with it, wake and sleep.
Many of the explanations for why we sleep circle around a common, and perhaps erroneous, idea: sleep is the state we must enter in order to fix that which has been upset by wake. But what if we turned this argument on its head? What if sleep is so useful — so physiologically beneficial to every aspect of our being — that the real question is: Why did life ever bother to wake up? Consider how biologically damaging the state of wakefulness can often be, that is the true evolutionary puzzle here, not sleep. Adopt this perspective, and we can pose a very different theory: sleep was the first state of life on this planet.”
“As with so many things in sleep, there’s another anomaly. Debate surrounds aquatic mammals. Certain of these ocean-faring species, such as dolphins or killer whales, buck the REM-sleep trend in mammals. They don’t have any. Although there is one case in 1969 suggesting that a pilot whale was in REM sleep for six minutes, most of our assessments to date have not discovered REM sleep — or at least what many sleep scientists would believe to be true REM sleep — in aquatic mammals. From one perspective, this makes sense: when an organism enters REM sleep, the brain paralyzes the body, turning it limp and immobile. Swimming is vital for aquatic mammals, since they must surface to breathe. If full paralysis was to take hold during sleep, they could not swim and would drown.
The mystery deepens when we consider pinnipeds (from the Latin derivatives: pinna ‘fin’ and pedis ‘foot’), such as fur seals. Partially aquatic mammals, they split their time between land and sea. When on land, they have both NREM sleep and REM sleep, just like humans and all other terrestrial mammals and birds. But when they enter the ocean, they stop having REM sleep almost entirely. Seals in the ocean will sample but a soupcon of the stuff, racking up just 5–10% of the REM sleep amounts they’d normally enjoying when on land. Up to two weeks of ocean-bound time have been documented without any observable REM sleep in seals, who survive in such times on a snooze diet of NREM sleep.
These anomalies do not necessarily challenge the usefulness of REM sleep. Without doubt, REM sleep, and even dreaming, appears to be highly useful and adaptive in those species that have it. That REM sleep returns when these animals return to land, rather being done away with entirely, affirms this. It’s simply that REM sleep doesn’t appear to be feasible or needed by aquatic mammals when in the ocean. During that time, we assume they make do with lowly NREM sleep — which, for dolphins and whales, may always be the case.
Personally, I don’t believe aquatic mammals, even cetaceans like dolphins and whales, have a total absence of REM sleep. Instead, I think the form of REM sleep these mammals obtain in the ocean is somewhat different and harder to detect: be it brief in nature, occurring at times when we haven’t been able to observe it, or expressed in ways or hiding in parts of the brain that we have not yet been able to measure.”
“A striking difference in sleep across the animal kingdom is the way in which we all do it. Here, the diversity is remarkable and, in some cases, almost impossible to believe. Take dolphins and whales, for example. Their sleep, of which there is only NREM, can be unihemispheric, meaning they will sleep with half a brain at at time! One half of the brain must always stay awake to maintain life-necessary movement in the aquatic environment. But the other half of the brain will, at times, fall into the most beautiful NREM sleep. Deep, powerful, rhythmic, and slow brainwaves will drench the entirety of one cerebral hemisphere, yet the other half of the cerebrum will be bristling with frenetic, fast brainwave activity, fully awake. This despite the fact that both hemispheres are heavily wired together with thick crisscross fibers, and sit mere millimetres apart, as in human brains.
Of course, both halves of the dolphin brain can be, and frequently are, awake at the very same time, operating in unison. But when it’s time for sleep, the two sides of the brain can uncouple and operate independently. After one half of the brain has consumed its fill of sleep, they switch, allowing the previously vigilant half of the brain to enjoy a well-earned period of deep NREM slumber. Even with half of the brain asleep, dolphins can achieve an impressive level of movement and even some vocalized communication.”
“The gift of split-brain deep NREM sleep is not entirely unique to aquatic mammals. Birds can do it, too. However, there’s a somewhat different, though equally life-preserving, reason: it allows them to keep an eye on things, quite literally. When birds are alone, one half of the brain and its corresponding (opposite) eye must stay awake, maintaining vigilance to environmental threats. As it does so, the other eye closes, allowing its corresponding half of the brain to sleep.
Things get even more interesting when birds group together. In some species, many of the birds in a flock will sleep with both halves of the brain at the same time. How do they remain safe from threat? The answer is truly ingenious. The flock will first line up in a row. With the exception of the birds at each end of the line, the rest of the group will allow both halves of the brain to indulge in sleep. Those at the far left and right ends of the row aren’t so lucky. They will enter deep sleep with just one half of the brain (opposing in each), leaving the corresponding left and right eye of each bird wide open. In doing so, they provide full panoramic threat detection for the entire group, maximizing the total number of brain halves that can sleep within the flock. At some point, the two end-guards will stand up, rotate 180 degrees, and sit back down, allowing the other side of their respective brains to enter deep sleep.”
“Two recently published reports suggest humans have a very mild version of unihemispheric sleep — one that’s drawn out for similar reasons. If you compare the electrical depth of the deep NREM slow brainwaves on one half of someone’s head relative to the other when they’re sleeping at home, they’re about the same. But if you bring that person into a sleep lab, or take them to a hotel — both of which are unfamiliar sleep environments — one half of the brain sleeps a little lighter than the other, as if it’s standing guard with just a tad more vigilance due to the potentially less safe context that the conscious brain has registered while awake. The more nights an individual sleeps in the new location, the more similar the sleep is in each half of the brain. It is perhaps the reason why so many of us sleep so poorly the first night in a hotel room.
This phenomenon, however, doesn’t come close to the complete division between full wakefulness and truly deep NREM sleep achieved by each side of birds’ and dolphins’ brains. Humans always have to sleep with both halves of our brain in some state of NREM sleep. Imagine, though, the possibilities that would become available if only we could rest our brains, one half at a time.
REM sleep is strangely immune to being split across both sides of the brain, no matter who you are. All birds, irrespective of the environmental situation, always sleep with both halves of the brain during REM sleep.”
“Place an organism under conditions of severe famine, and foraging for food will supersede sleep. Nourishment will, for a time, push aside the need for sleep, though it cannot be sustained for long. Starve a fly and it will stay awake longer, demonstrating a pattern of food-seeking behavior. The same is true for humans. Individuals who are deliberately fasting will sleep less as the brain is tricked into thinking that food has suddenly become scarce.
Another rare example is the joint sleep deprivation that occurs in female killer whales and their newborn calves. Female killer whales give birth to a single calf once every three to eight years. Calving normally takes place away from the other members of the pod. This leaves the newborn calf incredibly vulnerable during the initial weeks of life, especially during the return to the pod as it swims beside its mother. Up to 50% of all new calves are killed during this journey home. It’s so dangerous, in fact, that neither mother nor calf appear to sleep while in transit.”
“The white-crowned sparrow is perhaps the most astonishing example of avian sleep deprivation during long-distance flights. This small, quotidian bird is capable of a spectacular feat that the American military has spent millions of research dollars studying. The sparrow has an unparalleled, though time-limited, resilience to total sleep deprivation, one that we humans could never withstand. If you sleep-deprive this sparrow in the lab during the migratory period of the year (when it would otherwise be in flight), it suffers virtually no ill effects whatsoever. However, depriving the same sparrow of the same amount of sleep outside this migratory time window inflicts a maelstrom of brain and body dysfunction. This humble passerine bird has evolved an extraordinary biological cloak of resilience to total sleep deprivation.”
“My theory is that the tree-to-ground reengineering of sleep was a key trigger that rocked Homo sapiens to the top of evolution’s lofty pyramid. At least two features define human beings relative to other primates. I posit that both have been beneficially and causally shaped by the hand of sleep, and specifically our intense degree of REM sleep relative to all other mammals: 1) our degree of sociocultural complexity, and 2) our cognitive intelligence; REM sleep, and the act of dreaming itself, lubricates both of these human traits.
To the first of these points, we have discovered that REM sleep exquisitely recalibrates and fine-tunes the emotional circuits of the human brain. In this capacity, REM sleep may very well have accelerated the richness and rational control of our initially primitive emotions, a shift that I propose critically contributed to the rapid rise of Homo sapiens to dominance over all other species in key ways.
We know, for example, that REM sleep increases our ability to recognize and therefore successfully navigate the kaleidoscope of socioemotional signals that are abundant in human culture, such as overt and covert facial expressions, major and minor bodily gestures, and even mass group behavior. One only needs to consider disorders such as autism to see how challenging and different a social existence can be without these emotional navigation abilities being fully intact.
Related, the REM-sleep gift of facilitating accurate recognition and comprehension allows us to make more intelligent decisions and actions as a consequence. More specifically, the coolheaded ability to regulate our emotions each day — a key to what we call emotional IQ — depends on getting sufficient REM sleep night after night. (If your mind immediately jumped to particular colleagues, friends, and public figures who lack these traits, you may well wonder about how much late-morning REM-rich sleep they’re getting.)
Second, and more critical, if you multiply these individual benefits within and across groups and tribes, all of which are experiencing an ever-increasing intensity and richness of REM sleep over millennia, we can start to see how this nightly REM-sleep recalibration of our emotional brains could have scaled rapidly and exponentially. From this REM-sleep-enhanced emotional IQ emerged a new and far more sophisticated form of hominid socioecology across vast collectives, one that helped enable the creation of large, emotionally astute, stable, highly bonded, and intensely social communities of humans.”
“Our current understanding of what causes autism is incomplete, but central to the condition appears to be an inappropriate wiring up of the brain during early developmental life, specifically in the formation and number of synapses. Imbalances in synaptic connections are common in autistic individuals: excess amounts of connectivity in some parts of the brain, deficiencies in others.
Realizing this, scientists have begun to examine whether the sleep of individuals with autism is atypical. It is. Infants and young children who show signs of autism, or who are diagnosed with autism, do not have normal sleep patterns or amounts. The circadian rhythms of autistic children are also weaker than their non-autistic counterparts, showing a flatter profile of melatonin across the 24-hour period rather than a powerful rise in concentration at night and rapid fall throughout the day. Biologically, it is as if the day and night are far less light and dark, respectively, for autistic individuals. As a consequence, there’s a weaker signal for when stable wake and solid sleep should take place. Additionally, and perhaps related, the total amount of sleep autistic children can generate is less than that of non-autistic children.
Most notable, however, is the significant shortage of REM sleep. Autistic individuals show a 30–50% deficit in the amount of REM sleep they obtain, relative to children without autism. Considering the role of REM sleep in establishing the balanced mass of synaptic connections within the developing brain, there’s now keen interest in discovering whether or not REM-sleep deficiency is a contributing factor to autism. Existing evidence in humans is simply correlational, however.”
Napping
“The true pattern of biphasic sleep — for which, there’s anthropological, biological, and genetic evidence, and which remains measurable in all human beings to date — is one consisting of a longer bout of continuous sleep at night, followed by a shorter midafternoon nap.
Accepting that this is our natural pattern of slumber, can we even know for certain what types of health consequences have been caused by our abandonment of biphasic sleep? Biphasic sleep is still observed in several siesta cultures throughout the world, including regions of South America and Mediterranean Europe.”
“Prior to the turn of the millennium, there was increasing pressure to abandon the siesta-like practice in Greece. A team of researchers from Harvard’s School of Public Health decided to quantify the health consequences of this radical change in more than 23,000 Greek adults, which contained men and women 20–38 years old. The researchers focused on cardiovascular outcomes, tracking the group across a six-year period as the siesta practice came to an end for many of them.
As with countless Greek tragedies, the end result was heartbreaking, but here in the most serious, literal way. None of the individuals had a history of coronary heart disease or stroke at the start of the study, indicating the absence of cardiovascular ill health. However, those that abandoned regular siestas went on to suffer a 37% increased risk of death from heart disease across the six-year period, relative to those who maintained regular daytime naps. The effect was especially strong in workingmen, where the ensuing risk of not napping increased by well over 60%.
Apparent from this remarkable study is this fact: when we are cleaved from the innate practice of biphasic sleep, our lives are shortened. It’s perhaps unsurprising that in the small enclaves of Greece where siestas still remain intact, such as the island of Ikaria, men are nearly four times as likely to reach the age of ninety as American males. These napping communities have sometimes been described as ‘the places where people forget to die.’ From a prescription written long ago in our ancestral genetic code, the practice of natural biphasic sleep, and a healthy diet, appear to be the keys to a long-sustained life.”
Sleep Across The Lifetime
“Asking your teenager to go to bed and fall asleep at 10pm is the circadian equivalent of asking you, their parent, to go to sleep at 7 or 8pm. No matter how loud you enunciate the order, no matter how much that teenager truly wishes to obey your instruction, and no matter what amount of willed effort is applied by either of the two parties, the circadian rhythm of a teenager will not be miraculously coaxed into a change. Furthermore, asking that same teenager to wake up at seven the next morning and function with intellect, grace, and good mood is the equivalent of asking you, their parent, to do the same at 4 or 5am.”
“As you enter your fourth decade of life, there’s a palpable reduction in the electrical quantity and quality of that deep NREM sleep. You obtain fewer hours of deep sleep, and those deep NREM brainwaves become smaller, less powerful, and fewer in number. Passing into your mid- and late forties, age will have stripped you of 60–70% of the deep sleep you were enjoying as a young teen. By the time you reach 70, you’ll have lost 80–90% of that youthful deep sleep.
Certainly, when we sleep at night, and even when we wake in the morning, most of us do not have a good sense of our electrical sleep quality. Frequently this means that many seniors progress through their later years not fully realizing how degraded their deep-sleep quantity and quality have become. This is an important point: it means that elderly individuals fail to connect their deterioration in health with their deterioration to sleep, despite causal links between the two having been known to scientists for decades. Seniors therefore complain about and seek treatment for their health issues when visiting their GP, but rarely ask for help with their equally problematic sleep issues. As a result, GPs are rarely motivated to address the problematic sleep in addition to the problematic health concerns of the older adult.”
“Far more of our age-related physical and mental health ailments are related to sleep impairment than either we, or many doctors, truly realize or treat seriously.”
“The second hallmark of altered sleep as we age, and one that older adults are more conscious of, is fragmentation. The older we get, the more frequently we wake up throughout the night. There are many causes, including interacting medications and diseases, but chief among them is a weakened bladder. Older adults therefore visit the bathroom more frequently at night.
Due to sleep fragmentation, older individuals will suffer a reduction in sleep efficiency, defined as the percent of time you were asleep while in bed. As healthy teens, we enjoyed a sleep efficiency of about 95%. Most sleep doctors consider good-quality sleep to involve a sleep efficiency of 90% or above. By the time we reach our eighties, sleep efficiency has often dropped below 70 or 80%; 70–80% may sound reasonable until you realize that, within an eight-hour period in bed, it means that you will spend as much as 1–1.5 hours awake.
Insufficient sleep is no small thing, as studies assessing tens of thousands of older adults show. Even when controlling for other factors, the lower an older individual’s sleep efficiency score, the higher their mortality risk, the worse their physical health, the more likely they are to suffer from depression, the less energy they report, and the lower their cognitive function, typified by forgetfulness. Any individual, no matter what age, will exhibit physical ailments, mental health instability, reduced alertness, and impaired memory if their sleep is chronically disrupted. The problem in aging is that family members observe these daytime features in older relatives and jump to a diagnosis of dementia, overlooking the possibility that bad sleep is an equally likely cause. (Although sleep disruption is a causal factor contributing to dementia in mid- and later life.)
A more immediate, though equally dangerous, consequence of fragmented sleep in the elderly warrants brief discussion: the nighttime bathroom visits and associated risks of falls and their fractures. We’re often groggy when we wake up during the night. Add to this cognitive haze that it’s dark. Furthermore, having been recumbent in bed means that when you stand and start moving, blood can race from your head, encouraged by gravity, down toward your legs. You feel light-headed and unsteady on your feet as a consequence. The latter is especially true in older adults whose control of blood pressure is itself often impaired. All of these issues mean that an older individual is at far higher risk of stumbling, falling, and breaking bones during nighttime visits to the bathroom. Falls and fractures markedly increase morbidity and significantly hasten the end of life for an older adult.
The third sleep change with advanced age is that of circadian timing. In sharp contrast to adolescents, seniors commonly experience a regression in sleep timing, leading to earlier and earlier bedtimes. The cause is an earlier evening release and peak of melatonin as we get older, instructing an earlier start time for sleep. Restaurants in retirement communities have long known of this age-related shift in bedtime preferences, epitomized (and accommodated) by the ‘early-bird special.’
Changes in circadian rhythms with advancing age may appear harmless, but they can be the cause of numerous sleep (and wake) problems in the elderly. Older adults often want to stay awake later into the evening so they can go to the movies, socialize, or watch TV. But in doing so, they find themselves waking up on the couch, having inadvertently fallen asleep mid-evening. Their regressed circadian rhythm has left them no choice.
But what seems like an innocent doze has a damaging consequence. The early-evening snooze will jettison precious sleep pressure, clearing away the sleepiness power of adenosine that has been steadily building throughout the day. Several hours later, when the older individual gets into bed and tries to fall asleep, they may not have enough sleep pressure to fall asleep quickly, or stay asleep as easily. An erroneous conclusion follows: ‘I have insomnia.’ Instead, dozing off in the evening, which most older adults do not realize is classified as napping, can be the source of sleep difficulty, not true insomnia.
A compounding problem arrives in the morning. Despite having had trouble falling asleep that night and already running a sleep debt, the circadian rhythm will start to rise around 4 or 5am in many elderly individuals, enacting its classic earlier schedule in seniors. Older adults are therefore prone to wake up early in the morning as the alerting drumbeat of the circadian rhythm grows louder, and corresponding hopes of returning back to sleep diminish in tandem.
Making matters worse, the strengths of the circadian rhythm and amount of nighttime melatonin released also decrease the older we get. Add these things up, and a self-perpetuating cycle ensues wherein many seniors are battling a sleep debt, trying to stay awake later in the evening, inadvertently dozing off earlier, finding it hard to fall or stay asleep at night, only to be woken up earlier than they wish because of a regressed circadian rhythm.”
“Plentiful later-afternoon daylight will help delay the evening release of melatonin, helping push the timing of sleep to a later hour.”
“Older adults may also wish to consult with their doctor about taking melatonin in the evening. Unlike young or middle-age adults, where melatonin has not proved efficacious for helping sleep beyond the circumstance of jet lag, prescription melatonin has been shown to help boost the otherwise blunted circadian and associated melatonin rhythm in the elderly, reducing the time taken to fall asleep and improving self-reported sleep quality and morning alertness.”
“In the years leading up to these investigations, my research team and several others around the world had demonstrated how critical deep sleep was for cementing new memories and retaining new facts in young adults. Knowing this, we had included a twist to our experiment in older adults. Several hours before going to sleep, all of these seniors learned a list of new facts (word associations), quickly followed by an immediate memory test to see how much info they’d retained. The next morning, following the night of sleep recording, we tested them a second time. We could therefore determine the amount of memory savings that had occurred for any one individual across the night of sleep.
The older adults forgot far more of the facts by the following morning than the young adults — a difference of almost 50%. Furthermore, those older adults with the greatest loss of deep sleep showed the most catastrophic overnight forgetting. Poor memory and poor sleep in old age are therefore not coincidental, but rather significantly interrelated. The findings helped us shed new light on the forgetfulness that is all too common in the elderly.”
“The anatomical dialogue established during NREM sleep (using sleep spindles and slow waves) between the hippocampus and cortex is elegantly synergistic. By transferring memories of yesterday from the short-term repository of the hippocampus to the long-term home within the cortex, you awake with both yesterday’s experiences safely filed away and having regained your short-term storage capacity for new learning throughout that following day. The cycle repeats each day and night, clearing out the cache of short-term memory for the new imprinting of facts, while accumulating an ever-updated catalog of past memories. Sleep is constantly modifying the info architecture of the brain at night. Even daytime naps as short as twenty minutes can offer a memory consolidation advantage, so long as they contain enough NREM sleep.
Study infants, young kids, or adolescents, and you see the very same overnight memory benefit of NREM sleep, sometimes even more powerfully so. For those in midlife, deep NREM sleep continues to help the brain retain new info in this way, until the decline in deep NREM sleep and the deterioration of the ability to learn and retain memories in old age.”
Benefits on Memory and Performance
“We designed an experiment that used daytime naps. At middway, our research subjects studied a long list of words presented one at a time on a computer screen. After each word had been presented on the screen, however, a large green ‘R’ or a large red ‘F’ was displayed, indicating to the participant that they should remember the prior word (R) or forget the prior word (F). It’s not dissimilar to being in a class and, after having been told a fact, the teacher impresses upon you that it’s especially important to remember that info for the exam, or instead that they made an error and the fact was incorrect, or the fact won’t be tested, so you don’t need to worry about remembering it.
Half of the participants were then allowed a ninety-minute afternoon nap, while the other half remained awake. At six pm, we tested everyone’s memory for all of the words. We told participants that regardless of the tag previously associated with a word — to be remembered or to be forgotten — they should try to recall as many words as possible. Our question was this: Does sleep improve the retention of all words equally, or does sleep obey the waking command only to remember some items while forgetting others?
The results were clear. Sleep powerfully, yet very selectively, boosted the retention of those words previously tagged for ‘remembering,’ yet actively avoided the strengthening of those memories tagged for ‘forgetting.’ Participants who didn’t sleep showed no such impressive parsing and differential saving of the memories.
We’d learned a subtle, but important, lesson: sleep was far more intelligent than we’d once imagined. Counter to earlier assumptions in the 20th and 21st century, sleep doesn’t offer a general, nonspecific (and hence verbose) preservation of all the info you learn during the day. Instead, sleep is able to offer a far more discerning hand in memory improvement: one that preferentially picks and chooses what info is, and is not, ultimately strengthened. Sleep accomplishes this by using meaningful tags that have been hung onto those memories during initial learning, or potentially identified during sleep itself. Numerous studies have shown a similarly intelligent form of sleep-dependent memory selection across both daytime naps and a full night of sleep.”
“We’re now exploring ways of harnessing this remarkably intelligent service of selective remembering and forgetting with painful or problematic memories. My hope is to develop accurate methods for selectively weakening or erasing certain memories from an individual’s memory library when there’s a confirmed clinical need, such as trauma, drug addiction, or substance abuse.”
“I took a large group of right-handed individuals and had them learn to type a number sequence on a keyboard with their left hand, such as 4–1–3–2–4, as quickly and accurately as possible. Like learning a piano scale, subjects practiced the motor skill sequence over and over again, for a total of twelve minutes, taking short breaks throughout. Unsurprisingly, the participants improved in their performance across the training session. We then tested the participants 12 hours later. Half of them had learned the sequence in the evening and we retested them the next morning after a similar 12-hour delay, but one that contained a full eight-hour night of sleep.
Those who remained awake across the day showed no evidence of a significant improvement in performance. However, those who were tested after the very same time delay of 12 hours, but that spanned a night of sleep, showed a striking 20% jump in performance speed and a near 35% improvement in accuracy. Importantly, those participants who learned the motor skills in the morning — and who showed no improvement that evening — did go on to show an identical bump in performance when retested after a further 12 hours, now after they, too, had had a full night’s sleep.
In other words, your brain will continue to improve skill memories in the absence of any further practice. It is really quite magical Yet, that delayed, ‘offline’ learning occurs exclusively across a period of sleep, and not across equivalent time periods spent awake. Practice doesn’t make perfect. It’s practice, followed by a night of sleep, that leads to perfection.”
Sleep Deficiency
“After a poor night of sleep, participants consistently underestimated their degree of performance disability. Similarly problematic is baseline resetting. 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. Individuals fail to recognize how their perennial state of sleep deficiency has come to compromise their mental aptitude and physical vitality, including the slow accumulation of ill health. A link between the former and the latter is rarely made in the mind. Based on epidemiological studies of average sleep time, millions of individuals unwittingly spend years of their life in a sub-optimal state of psychological and physiological functioning, never maximizing their potential of mind or body due to their blind persistence in sleeping too little.”
“Researchers in Australia took two groups of healthy adults, one of whom they got drunk to the legal driving limit (.08% blood alcohol), the other of whom they sleep-deprived for a single night. Both groups performed a concentration test to assess attention performance, specifically the number of lapses. After being awake for 19 hours, people who were sleep-deprived were as cognitively impaired as those who were legally drunk. If you wake up at 7am and remain awake throughout the day, then go socialize until late in the evening and drink no alcohol, by the time you’re driving home at 2am, you’re as cognitively impaired in your ability to attend to the road and what’s around you as a legally drunk driver. In fact, participants in the above study started their nosedive in performance after just 15 hours of being awake (10pm in this scenario).
In 2016, the AAA Foundation released the results of an extensive study of over 7,000 drivers in the U.S., tracked in detail over a two-year period. The key finding was that drowsy driving is catastrophic. Operating on less than five hours of sleep increases your risk of a car crash threefold. Get behind the wheel of a car when having slept just four hours or less the night before and you’re 11.5 times more likely to be involved in a crash. Note how the relationship between decreasing hours of sleep and increasing mortality risk of an accident isn’t linear, but instead exponentially mushrooms. Each hour of sleep lost vastly amplifies that crash likelihood, rather than incrementally nudging it up.”
“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 seven hours of sleep each night to maintain cognitive performance. After ten days of just seven hours of sleep, the brain is as dysfunctional as it would be after going without sleep for 24 hours. Three 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.”
“Drowsy driving alone is worse than driving drunk. Drunk drivers are often late in braking and late in making evasive maneuvers. But when you fall asleep, you stop reacting altogether. A person who experiences a microsleep or who has fallen asleep at the wheel doesn’t brake at all, nor do they make any attempt to avoid the crash. As a result, car crashes caused by drowsiness tend to be far more deadly than those caused by alcohol or drugs. Said crassly, when you fall asleep at the wheel of your car on a freeway, there’s now a one-ton missile traveling at 65 miles per hour, and no one is in control.
Even more dangerous are drowsy truckers. Approximately 80% of truck drivers in the U.S. are overweight and 50% are obese. This places truck drivers at a far, far higher risk of sleep apnea, commonly associated with heavy snoring, which causes chronic, severe sleep deprivation. As a result, these truck drivers are 200–500% more likely to be involved in a traffic accident. And when a truck driver loses their life in a drowsy-driving crash, they will, on average, take 4.5 other lives with them.
Drowsy-driving deaths are neither chance, nor without cause. They’re predictable and the direct result of not obtaining sufficient sleep. As such, they’re unnecessary and preventable. Shamefully, governments of most developed countries spend less than 1% of their budget educating the public on the dangers of drowsy driving relative to what they invest in combating drunk driving.”
“We studied two groups of healthy young adults. One stayed awake all night, monitored under full supervision in my lab, while the other group slept normally that night. During the brain scanning session the next day, participants in both groups were shown the same 100 pictures that ranged from neutral in emotional content (e.g. a basket) to emotionally negative (e.g. a burning house). Using this emotional gradient of pictures, we were able to compare the increase in brain response to the increasingly negative emotional triggers.
Analysis of the brain scans revealed the largest effects I’ve measured in my research to date. The amygdala — a key hot spot for triggering strong emotions like anger, and linked to the fight-or-flight response — showed well over a 60% amplification in emotional reactivity in the participants who were sleep-deprived. In contrast, the brain scans of those who were given a full night’s sleep evinced a controlled, modest degree of reactivity in the amygdala, despite viewing the same images. It was as though, without sleep, our brain reverts to a primitive pattern of uncontrolled reactivity. We produce unmetered, inappropriate emotional reactions, and are unable to place events into a broader or considered context.”
“Sleep disturbance is a recognized hallmark associated with addictive substance use. Insufficient sleep also determines relapse rates in numerous addiction disorders, associated with reward cravings that are unmetered, lacking control from the rational head office of the brain’s prefrontal cortex. Relevant from a prevention standpoint, insufficient sleep during childhood significantly predicts early onset of drug and alcohol use in that same child during their later adolescent years, even when controlling for other high-risk traits, such as anxiety, attention deficits, and parental history of drug use.”
“Is pulling an all-nighter a wise idea for learning?We took a large group of individuals and assigned them to either a sleep group or a sleep deprivation group. Both groups remained awake normally across the first day. Across the following night, those in the sleep group obtained a full night of shut-eye, while those in the sleep deprivation group were kept awake all night under the watchful eye of trained staff in my lab. Both groups were then awake across the following morning. Around midday, we placed participants in an MRI and had them try to learn a list of facts, one at a time, as we took snapshots of their brain activity. Then we tested them to see how effective that learning had been. However, instead of testing them immediately after learning, we waited until they had had two nights of recovery sleep. We did this to make sure that any impairments we observed in the sleep-deprived group were not confounded by them being too sleepy or inattentive to recollect what they may very well have learned.
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. It’d be the difference between acing an exam and failing it miserably!
What was going wrong within the brain to produce these deficits? We compared the patterns of brain activity during attempted learning between the two groups, and focused our analysis on the hippocampus — the information ‘inbox’ of the brain that acquires new facts. There was lots of healthy, learning-related activity in the hippocampus in the participants who had slept the night before. However, when we looked at this same brain structure in the sleep-deprived participants, we couldn’t find any significantly learning activity whatsoever. It was as though sleep deprivation had shut down their memory inbox, and any new incoming info was simply being bounced. You don’t even need the blunt force of a whole night of sleep deprivation. Simply disrupting the depth of an individual’s NREM sleep with infrequent sounds, preventing deep sleep and keeping the brain in shallow sleep, without waking the individual up will produce similar brain deficits and learning impairments.
Those few memories you’re able to learn while sleep-deprived are forgotten far more quickly in the hours and days thereafter. Memories formed without sleep are weaker memories, evaporating rapidly.”
Sleep & Alzheimer’s
“Although the glymphatic system is somewhat active during the day, it’s during sleep that this neural sanitization work kicks into high gear. Associated with the pulsing rhythm of deep NREM sleep comes a ten to twentyfold increase in effluent expulsion from the brain. In what can be described as a nighttime power cleanse, the purifying work of the glymphatic system is accomplished by cerebrospinal fluid that bathes the brain.
The research unveiled a second astonishing discovery, which explained why the cerebrospinal fluid is so effective at flushing our metabolic debris at night. The glial cells of the brain were shrinking in size by up to 60% during NREM sleep, enlarging the space around the neurons and allowing the cerebrospinal fluid to proficiently clean out the metabolic refuse left by the day’s neural activity. Think of the buildings of a large city physically shrinking at night, allowing cleaning crews easy access to pick up garbage strewn in the streets, followed by a good pressure-jet treatment of every nook and cranny. When we wake each morning, our brains can once again function efficiently thanks to this deep cleaning.
One piece of toxic debris evacuated by the glymphatic system during sleep is amyloid protein — the poisonous element associated with Alzheimer’s. Other dangerous metabolic waste elements that have links to Alzheimer’s are also removed by the cleaning process during sleep, including stress molecules produced by neurons when they combat energy and oxygen during the day. Should you experimentally prevent a mouse from getting NREM sleep, keeping it awake instead, there’s an immediate increase in amyloid deposits within the brain. Without sleep, an escalation of poisonous Alzheimer’s-related protein accumulated in the brains of the mice, together with several other toxic metabolites. Phrased differently, wakefulness is low-level brain damage, while sleep is neurological sanitation.
Inadequate sleep and the pathology of Alzheimer’s interact in a vicious cycle. Without sufficient sleep, amyloid plaques build up in the brain, especially in deep-sleep-generating regions, attacking and degrading them. The loss of deep NREM sleep caused by this assault therefore lessens the ability to remove amyloid from the brain at night, resulting in greater amyloid deposition. More amyloid, less deep sleep, less deep sleep, more amyloid, and so on.
From this cascade comes a prediction: getting too little sleep across the adult lifespan will significantly increase your risk of developing Alzheimer’s. Precisely this relationship has now been reported in numerous epidemiological studies, including those individuals suffering from sleep disorders such as insomnia and sleep apnea.”
“By improving someone’s sleep, we should be able to reduce their risk of developing Alzheimer’s — or at least delay its onset. Tentative support has emerged from clinical studies in which middle- and older-aged adults have had their sleep disorders successfully treated. As a consequence, their rate of cognitive decline slowed significantly, and further delayed the onset of Alzheimer’s by 5–10 years.”
Sleep & The Heart
“Unhealthy sleep, unhealthy heart: simple and true. Take the results of a 2011 study that tracked more than half a million diverse men and women across eight different countries. Progressively shorter sleep was associated with a 45% increased risk of developing and/or dying from coronary heart disease within 7–25 years from the start of the study. A similar relationship was observed in a Japanese study of over 4,000 male workers. Over a 14-year period, those sleeping six hours or less were 400–500% more likely to suffer one or more cardiac arrests than those sleeping more than six hours, even after accounting for other risk factors.
As we approach midlife, and our body begins to deteriorate and health resilience starts its decline, the impact of insufficient sleep on the cardiovascular system escalates. Adults 45+ who sleep fewer than six hours a night are 200% more likely to have a heart attack or stroke during their lifetime, as compared with those sleeping 7–8 hours a night.”
“An acute stress response from the sympathetic nervous system, which is normally only deployed for short periods of time lasting minutes to hours, can be highly adaptive under conditions of credible threat, such as the potential of real physical attack. Survival is the goal, and these responses promote immediate action to accomplish just that. But leave that system stuck in the ‘on’ position for long durations of time, and sympathetic activation becomes deeply maladaptive. In fact, it’s a killer.
With few exceptions over the past half century, every experiment that’s investigated the impact of deficient sleep on the human body has observed an overactive sympathetic nervous system. For as long as the state of insufficient sleep lasts, and for some time thereafter, the body remains stuck in some degree of a fight-or-flight state. It can last for years in those with an untreated sleep disorder, excessive work hours that limit sleep or its quality, or the simple neglect of sleep. Like a car engine that’s revved to a shrieking extreme for sustained periods of time, your sympathetic nervous system is floored into perpetual overdrive by a lack of sleep. The consequential strain that’s placed on your body by the persistent force of sympathetic activation will leak out in all manner of health issues, just like the failed parts of an abused car engine.
Through this central pathway of an overactive sympathetic nervous system, sleep deprivation triggers a domino effect that will spread like a wave of health damage throughout your body. It starts with removing a default resting brake that normally prevents your heart from accelerating its rate of contraction. Once this brake is released, you’ll experience sustained speeds of cardiac beating.
As your sleep-deprived heart beats faster, the volumetric rate of blood pumped through your vasculature increases, and with that comes the hypertensive state of your blood pressure. Occurring at the same time is a chronic increase in a stress hormone called cortisol, which is triggered by the overactive sympathetic nervous system. One undesirable consequence of the sustained deluge of cortisol is the constriction of those blood vessels, triggering an even greater increase in blood pressure.
Making matters worse, growth hormone — a great healer of the body — which normally surges at night, is shut off by the state of sleep deprivation. Without growth hormone to replenish the lining of your blood vessels, they’ll be slowly shorn and stripped of their integrity. Adding insult to real injury, the hypertensive strain that sleep deprivation places on your vasculature means that you can no longer repair those fracturing vessels effectively. The damaged and weakened state of vascular plumbing throughout your body now becomes systematically more prone to arteries furring up. Vessels will rupture. It’s a powder keg of factors, with heart attack and stroke being the most common casualties in the explosive aftermath.
Compare this cascade of harm to the healing benefits that a full night of sleep normally lavishes on the cardiovascular system. During deep NREM sleep specifically, the brain communicates a calming signal to the fight-or-flight sympathetic branch of the body’s nervous system, and does so for long durations of the night. As a result, deep sleep prevents an escalation of this physiological stress that’s synonymous with increased blood pressure, heart attack, heart failure, and stroke. This includes a calming effect on the contracting speed of your heart. Think of your deep NREM sleep as a natural form of nighttime blood-pressure management — one that averts hypertension and stroke.”
“Each year there’s a global experiment in which 1.5 billion people are forced to reduce their sleep by one hour or less for a single night. This experiment is otherwise known as Daylight Savings Time.
In the Northern Hemisphere, the switch to daylight savings in March results in most people losing an hour of sleep opportunity. Should you tabulate millions of daily hospital records, as researchers have done, you discover that this seemingly trivial sleep reduction comes with a frightening spike in heart attacks the following day. Impressively, it works both ways. In the autumn within the Northern Hemisphere, when the clocks move forward and we gain an hour of sleep opportunity time, rates of heart attacks plummet the day after. A similar rise-and-fall relationship can be seen with the number of traffic crashes, proving that the brain, by way of attention lapses and microsleeps, is just as sensitive as the heart to very small perturbations of sleep. Most people think nothing of losing an hour of sleep for a single night, believing it to be trivial and inconsequential. It is anything but.”
Sleep & Hormones
“Take a group of lean, healthy young males in their mid-20s and limit them to five hours of sleep for one week, as a research group did. Sample the hormone levels circulating in the blood of these tired participants and you’ll find a marked drop in testosterone relative to their own baseline levels of testosterone when fully rested. The size of the hormonal blunting effect is so large that it effectively ‘ages’ a man by 10–15 years in terms of testosterone virility. The experimental results support the finding that men suffering from sleep disorders have significantly lower levels of testosterone.
Men who report sleeping too little or having poor-quality sleep have a 29% lower sperm count than those obtaining a full and restful night of sleep, and the sperm themselves have more deformities. These under-slept men also have significantly smaller testicles than their well-rested counterparts.
Low testosterone is a clinically concerning and life-impacting matter. Males with low testosterone often feel tired and fatigued throughout the day. They find it difficult to concentrate on work tasks, as testosterone has a sharpening effect on the brain’s ability to focus. And of course, they have a dulled libido, making an active, fulfilling, and healthy sex life more challenging. Indeed, the self-reported mood and vigor of the young men described in the above study progressively decreased in lockstep with their increasing state of sleep deprivation and their declining levels of testosterone. Add to this the fact that testosterone maintains bone density, and plays a causal role in building muscle mass and therefore strength, and you can begin to get a sense of why a full night of sleep — and the natural hormonal replacement therapy it provides — is so essential to this aspect of health for men.”
“Men aren’t the only ones who become reproductively compromised by a lack of sleep. Routinely sleeping less than six hours a night results in a 20% drop in follicular-releasing hormone in women — a critical female reproductive element that peaks just prior to ovulation and is necessary for conception. In a report that compiled forty years of studies of more than 100,000 employed women, those working irregular nighttime hours resulting in poor-quality sleep had a 33% higher rate of abnormal menstrual cycles than those working regular hours. Moreover, the women working erratic hours were 80% more likely to suffer from issues of sub-fertility that reduced the ability to get pregnant. Women who do become pregnant and routinely sleep less than eight hours a night are also significantly more likely to suffer a miscarriage in the first trimester, relative to those consistently sleeping 8+ hours a night.”
Sleep & Attractiveness
“A colleague took a group of healthy men and women 18–31 years old. They were all photographed twice under identical lighting conditions, same time of day, hair down, no makeup, clean-shaven. What differed, however, was the amount of sleep these individuals were allowed to get before each of the photo shoots. In one of the sessions, the participants were given just five hours of sleep before being put in front of the camera, while in the other session, these same individuals got a full eight hours of sleep. The order of these two conditions was randomized as either first or second across the unwitting models.
She brought another group into the lab to act as judges, who viewed both sets of pictures in a jumbled order and were asked to give ratings on three features: perceived health, tiredness, and attractiveness. Despite knowing nothing about the underlying premise of the study, the judges’ scores were unambiguous. The faces pictured after one night of short sleep were rated as looking more fatigued, less healthy, and significantly less atrractive, compared with the appealing image of the same individual after they’d slept a full eight hours. She’d revealed the true face of sleep loss, and with it, ratified the long-held concept of ‘beauty sleep.’”
Weight Loss & Sleep
“In a group of healthy, lean participants, a researcher discovered that individuals were far more ravenous when sleeping four to five hours a night. This despite being given the same amount of food and being similarly active, which kept the hunger levels of these same individuals under calm control when they were getting 8+ hours of sleep. The strong rise of hunger pangs and increased reported appetite occurred rapidly, by just the second day of short sleeping.
At fault were the two characters, leptin and ghrelin. Inadequate sleep decreased concentrations of the safety-signaling hormone leptin and increased levels of the hunger-instigating hormone ghrelin. It was a classic case of psychological double jeopardy: by muting the chemical message that says ‘stop eating’ (leptin), yet increasing the hormonal voice that shouts ‘please, keep eating’ (ghrelin), your appetite remains unsatisfied when your sleep is anything less than plentiful. A sleep-deprived body will cry famine in the midst of plenty.
But feeling hungry and actually eating more are not the same thing. Does your waistline really swell as a consequence of that rise in appetite? The researcher proved this to be true. When short sleeping (4.5 hours a night), the very same individuals ate 300 calories more each day — or well over 1,000 calories before the end of the experiment — compared to when they were routinely getting a full night of sleep. Similar changes occur if you give people 5–6 hours of sleep over a ten-day period. Scale that up to a working year, and assuming one month of vacation in which sleep miraculously becomes abundant, and you’ll still have consumed more than 70,000 extra calories, which would cause 10–15 pounds of weight gain a year.”
“Three-year-olds sleeping just 10.5 hours or less have a 45% increased risk of being obese by age seven than those who get 12 hours of sleep a night.”
“When given just 5.5 hours of sleep opportunity, more than 70% of the pounds lost in a dieting study came from lean body mass — muscle. Switch to the group offered 8.5 hours’ time in bed each night and a far more desirable outcome was observed, with well over 50% of weight loss coming from fat while preserving muscle. When you’re not getting enough sleep, the body becomes especially stingy about giving up fat.”
Sleep & The Immune System & Cancer
“Participants in a study who obtained 7–9 hours’ sleep in the week before getting a flu shot generated a powerful antibody reaction, reflecting a robust, healthy immune system. In contrast, those in the sleep-deprived group mustered a paltry response, producing less than 50% of the immune reaction their well-slept counterparts were able to mobilize.
Even if an individual is allowed two or even three weeks of recovery sleep to get over the assault of one week of short sleeping, they never go on to develop a full immune reaction to the flu shot. In fact, a diminution in certain immune cells could still be observed a year later in the participants after just a minor, short dose of sleep restriction.”
“It doesn’t require many nights of short sleeping before the body is rendered immunologically weak, and here the issue of cancer becomes relevant. Natural killer cells are an elite and powerful squadron within the ranks of your immune system. Think of them like secret service agents whose job it is to identify dangerous foreign elements and eliminate them.
One such foreign entity that natural killer cells will target are malignant (cancerous) tumor cells. Natural killer cells will effectively punch a hole in the outer surface of these cancerous cells and inject a protein that can destroy the malignancy. What you want, therefore, is a virile set of these cells at all times. That’s precisely what you don’t have when sleeping too little.
Landmark UCLA studies have revealed just how quickly and comprehensively a brief dose of short sleep can affect your cancer-fighting immune cells. Examining healthy young men, the study demonstrated that a single night of four hours of sleep swept away 70% of the natural killer cells circulating in the immune system, relative to an eight-hour night of sleep. You could well imagine the enfeebled state of your cancer-fighting immune armory after a week of short sleep, let alone months or years.
We don’t have to imagine. A number of prominent epidemiological studies have reported that nighttime shift work, and the disruption to circadian rhythms and sleep that it causes, up your odds of developing numerous different forms of cancer considerably. To date, these include associations with cancer of the breast, prostate, uterus wall, endometrium, and colon.
Stirred by the strength of accumulating evidence, Denmark recently became the first country to pay worker comp to women who’d developed breast cancer after years of night-shift work in government-sponsored jobs, like nurses and air cabin crew. Other countries have resisted.
With each passing year of research, more forms of malignant tumors are being linked to insufficient sleep. A large European study of 25,000 individuals demonstrated that sleeping six hours or less was associated with a 40% increased risk of developing cancer, relative to those sleeping seven hours a night or more. Similar associations were found in a study of 75,000 women across an 11-year period.”
“In a University of Chicago study, mice were first injected with malignant cells, and tumor progression was then tracked across a four-week period. Half of the mice were allowed to sleep normally during this time; the other half had their sleep partially disrupted, reducing sleep quality.
The sleep-deprived mice suffered a 200% increase in the speed and size of their cancer growth, relative to the well-rested ones. When the researcher performed postmortems of the mice, he discovered that the tumors were far more aggressive in the sleep-deficient animals. Their cancer had metastasized, spreading to surrounding organs, tissue, and bone. When cancer metastasizes, medical intervention often becomes helplessly ineffective, and death rates escalate.”
Dreaming
“REM sleep is not the only time during sleep when we dream. Indeed, if you use a liberal definition of dreaming as any mental activity reported upon awakening, such as ‘I was thinking about rain,’ then you technically dream in all stages of sleep. If I wake you from the deepest stage of NREM sleep, there’s a 0–20% chance you’ll report some type of bland thought like this. As you’re falling asleep or exiting sleep, the dream-like experiences you have tend to be visually or movement-based. But dreams as most of us would think of them — those hallucinogenic, motoric, emotional, and bizarre experiences with a rich narrative — come from REM sleep, and many sleep researchers limit their definition of true dreaming to that which occurs in REM sleep.”
“If the brain cannot divorce the emotion from memory across the first night following a trauma experience, it seems that a repeat attempt of emotional memory will occur on the second night, as the strength of the ‘emotional tag’ associated with the memory remains too high. If the process fails a second time, the same attempt will continue to repeat the next night, and the next night, like a broken record. This was precisely what appeared to be happening with the recurring nightmares of the trauma experience in PTSD patients. A testable prediction emerged: if I could lower the levels of nonadrenaline in the brains of PTSD patients during sleep, thereby reinstating the right chemical conditions for sleep to do its trauma therapy work, then I should be able to restore healthier quality REM sleep and improve the clinical symptoms.”
“Confirming the importance of the dream state, the better the quality of REM sleep from one individual to the next across that rested night, the more precise the tuning within the emotional decoding networks of the brain the next day. Through this platinum-grade nocturnal service, better REM-sleep quality at night provided superior comprehension of the social world the next day.
But when those same participants were deprived of sleep, including the essential influence of REM sleep, they could no longer distinguish one emotion from another with accuracy. The tuning V of the brain had been changed, rudely pulled all the way up from the base and flattened into a horizontal line, as if the brain was in a state of generalized hypersensitivity without the ability to map gradiations of emotional signals from the outside world. Gone was the precise ability to read giveaway clues in another’s face. The brain’s emotional navigation system had lost its true magnetic north of directionality and sensitivity: a compass that otherwise guides us toward numerous evolutionary advantages.
With the absence of such emotional acuity, normally gifted by the re-tuning skills of REM sleep at night, the sleep-deprived participants slipped into a default of fear bias, believing even gentle or somewhat friendly faces were menacing. The outside world had become a more threatening and aversive place when the brain lacked REM sleep — untruthfully so. Reality and perceived reality were no longer the same in the ‘eyes’ of the sleepless brain. By removing REM sleep, we had, quite literally, removed participants’ levelheaded ability to read the social world around them.
Now think of occupations that require individuals to be sleep-deprived, such as police and military, doctors, nurses — not to mention the ultimate caretaking job: new parents. Everyone of these roles demands the accurate ability to read the emotions of others in order to make critical, even life-dependent, decisions, such as detecting a true threat that requires the use of weapons, assessing emotional discomfort or anguish that can change a diagnosis, the extent of pain meds prescribed, or deciding when to express compassion or dispense an assertive parenting lesson. Without REM sleep and its ability to reset the brain’s emotional compass, those same individuals will be inaccurate in their social and emotional comprehension of the world around them, leading to inappropriate decisions and actions that may have grave consequences.”
“It is sleep that builds connections between distantly related informational elements that aren’t obvious in the light of the waking day. Our participants went to bed with disparate pieces of the jigsaw and woke up with the puzzle complete. It’s the difference between knowledge (retention of individual facts) and wisdom (knowing what they all mean when you fit them together). Or, said more simply, learning vs. comprehension. REM sleep allows your brain to move beyond the former and truly grasp the latter.
Some may consider this informational daisy-chaining to be trivial, but it’s one of the key operations differentiating your brain from your computer. Computers can store thousands of individual files with precision. But standard computers don’t intelligently interlink those files in numerous and creative combinations. Instead, files sit like isolated islands. Our human memories are, on the other hand, richly interconnected in webs of associations that lead to flexible, predictive powers. We have REM sleep, and the act of dreaming, to thank for much of that inventive hard work.”
“Steinbeck wrote, ‘A problem difficult at night is resolved in the morning after the committee of sleep has worked on it.’ Should he have prefaced ‘committee’ with ‘dream’? It appears so. The content of one’s dreams, more than simply dreaming per se, or even sleeping, determines problem-solving success. Though such a claim has long been made, it took the advent of virtual reality for us to prove as much — and in the process, shore up the claims of nocturnal troubleshooters.
My collaborator designed a clever experiment in which participants explored a computerized virtual reality maze. During an initial learning session, he would start participants off from different random locations within the maze and ask them to navigate their way out through exploratory trial and error. To aid their learning, he placed unique objects, such as a Christmas tree, to act as orientation or anchor points at specific locations within the maze.
Almost 100 research participants explored the maze during the first learning session. Thereafter, half of them took a 90-minute nap, while the other half remained awake and watched a video, all monitored with electrodes placed on the head and face. Throughout the 90-minute epoch, he would occasionally wake the napping individuals and ask them about the content of any dreams they were having, or for the group that remained awake, askt hem to report any particular thoughts that were going through their minds at the time. Following the 90-minute period, and after another hour or so to overcome sleep inertia in those who’d napped, everyone was dropped back into the virtual maze and tested once more to see if their performance was any better than during initial testing.
It should come as no surprise by now that those participants who took a nap showed superior memory performance on the maze task. They could locate the navigation clues with ease, finding their way around and out of the maze faster than those who hadn’t slept. The novel result, however, was the difference that dreaming made. Participants who slept and reported dreaming of elements of the maze, and themes around experiences clearly related to it, showed almost 10x more improvement in their performance than those who slept just as much, and also dreamed, but didn’t dream of maze-related experiences.
The dreams of these super-navigators were not a precise replay of the initial learning experience while awake. For example, one participant’s dream report stated: ‘I was thinking about the maze and kinda having people as checkpoints, I guess, and then that led to me to think about when I went on this trip a few years ago and we went to see these bat caves, and they’re kind of like, maze-like.’ There were no bats in the virtual maze, nor were there any other people or checkpoints. Clearly, the dreaming brain wasn’t simply recapitulating or re-creating exactly what happened to them in the maze. Rather, the dream algorithm was cherry-picking salient fragments of the prior learning experience, and then attempting to place those new experiences within the back catalog of preexisting knowledge.
Like an insightful interviewer, dreaming takes the approach of interrogating our recent autobiographical experience and skillfully positioning it within the context of past experiences and accomplishments, building a rich tapestry of meaning. ‘How can I understand and connect that which I have recently learned with that I already know, and in doing so, discover insightful new links and revelations?’ Moreover, ‘What have I done in the past that might be useful in potentially solving this newly experienced problem in the future?’ Different from solidifying memories, which we now realize to be the job of NREM sleep, REM sleep, and the act of dreaming, takes that which we have learned in one experience setting and seeks to apply it to others stored in memory.”
“It remains unclear whether lucid dreaming is beneficial or detriental, since well over 80% of the general populace are not natural lucid dreamers. If gaining voluntary dream control were so useful, surely Mother Nature would have imbued the masses with such a skill.
However, this argument makes the erroneous assumption that we’ve stopped evolving. It’s possible that lucid dreamers represent the next iteration in Homo sapiens’ evolution. Will these individuals be preferentially selected for in the future, in part on the basis of this unusual dreaming ability — one that may allow them to turn the creative problem-solving spotlight of dreaming on to the waking challenges faced by themselves or the human race, and advantageously harness its power more deliberately?”
Sleep Disorders
“Somnambulism refers to sleep disorders that involve some form of movement. It encompasses conditions such as sleepwalking, sleep talking, sleep eating, sleep texting, sleep sex, and, very rarely, sleep homicide.
Understandably, most people believe these events happen during REM sleep as an individual is dreaming, and specifically acting out ongoing dreams. However, 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.
While we don’t yet fully understand the cause of somnambulism episodes, the existing evidence suggests that an unexpected spike in nervous system activity during deep sleep is one trigger. This electrical jolt compels the brain to rocket from the basement of deep NREM sleep all the way to the penthouse of wakefulness, but it gets stuck somewhere in between (the 13th floor, if you will). Trapped between the two worlds of deep sleep and wakefulness, the individual is confined to a state of mixed consciousness — neither awake nor asleep. In this confused condition, the brain performs basic but well-rehearsed actions, such as walking over to a closet and opening it, placing a glass of water to the lips, or uttering a few words of sentences.”
“For the most part, there’s nothing pathological about sleepwalking or sleep talking. They’re common in the adult population, and even more common in children. It’s not clear why children experience it more than adults, nor is it clear why some children grow out of having these nighttime events, while others will continue to do so throughout their lives. One explanation of the former is simply the fact that we have greater amounts of NREM sleep when we’re young, and therefore the statistical likelihood of sleepwalking and sleep talking episodes occurring is higher.
Most episodes are harmless. Occasionally, however, adult somnambulism can result in a much more extreme set of behaviors, such as those performed by Kenneth Parks in 1987. Parks, 23 at the time, lived with his wife and five-month-old daughter in Toronto. He’d been suffering from severe insomnia caused by the stress of joblessness and gambling debts. By all accounts, he was nonviolent. His mother-in-law — with whom he had a good relationship — called him a ‘gentle giant’ on the basis of his placid nature yet considerable height (he stood 6'4" and weighed 225). Then came May 23.
After falling asleep on the couch around 1:30am while watching TV, Parks arose and got in his car, barefoot, driving about 14 miles to his in-laws’ house. Upon entering, he made his way upstairs, stabbed his mother-in-law to death with a knife he’d taken from their kitchen, and strangled his father-in-law unconscious after similarly attacking him with a cleaver (his father-in-law survived). Parks then got back in his car and, upon regaining full waking consciousness at some point, drove to a police station and said, “I think I have killed some people…my hands.’ Only then did he realize the blood flowing down his arms as a result of severing his own flexor tendons with the knife.
Since he could remember only vague fragments of the murder (e.g. flashes of his mother-in-law’s face with a ‘help me’ look on it), had no motive, and had a long history of sleepwalking (as did other members of his family), a team of defense experts concluded that Parks was asleep when he committed the crime, suffering a severe episode of sleepwalking. They argued that he was unaware of his actions, and thus not culpable. In 1988, a jury rendered a verdict of not guilty. This defense has been attempted in a number of subsequent cases, most of which have been unsuccessful.”
“Clinical insomnia requires an ongoing duration of sleep difficulty, week after week after week. Even with this strict definition, chronic insomnia is disarmingly common. Approximately 1 in 9 people will meet the strict clinical criteria for insomnia, which translates to more than 40 million Americans struggling to make it through their waking days due to wide-eyed nights. While the reasons remain unclear, insomnia is almost twice as common in women than in men, and it’s unlikely that a simple unwillingness of men to admit sleep problems explains this very sizable difference between the sexes. Black and Latinx Americans suffer high rates than whites — findings that have important implications for well-recognized health disparities in these communities, such as diabetes, obesity, and cardiovascular disease, which have known links to a lack of sleep.
In truth, insomnia is likely to be a more widespread and serious problem than even these sizable numbers suggest. Should you relax the stringent clinical criteria and just use epidemiological data as a guide, it’s probable than 2 in 3 people will regularly have difficulty falling or staying asleep at least one night a week, every week. 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’s a need to act.”
“Michael Corke became the man who could not sleep — and paid for it with his life. Before the insomnia took hold, he was an active individual, a devoted husband, and a music teacher near Chicago. At age 40 he began having trouble sleeping. At first, Corke felt that his wife’s snoring was to blame. In response to this suggestion, he decided to sleep on the couch for the next ten nights. His insomnia didn’t abate, and only became worse. After months of poor sleep, and realizing the cause lay elsewhere, he decided to seek medical help. None of the doctors who first examined Corke could identify the trigger of his insomnia, and some diagnosed him with sleep-unrelated disorders, like MS.
Corke’s insomnia eventually progressed to the point where he was completely unable to sleep. No mild sleep medicines or even heavy sedatives could wrestle his brain from the grip of permanent wakefulness. Should you have observed him at this time, it would be clear how desperate he was for sleep. His eyes would make your own feel tired. His blinks were achingly slow, as if the eyelids wanted to stay shut, mid-blink, and not re-open for days.
After eight straight weeks of no sleep, Corke’s mental facilities were quickly fading. This cognitive decline was matched in speed by the rapid deterioration of his body. So compromised were his motor skills that even coordinated walking became difficult. As Corke approached the six-month mark of no sleep, he was bedridden and approaching death. Despite his young age, his neurological condition resembled that of an elderly individual in the end stages of dementia. He couldn’t bathe or clothe himself. Hallucinations and delusions were rife. His ability to generate language was all but gone, and he was resigned to communicating through rudimentary head movements and rare inarticulate utterances whenever he could muster the energy. Several more months of no sleep and Corke’s body and mental faculties shut down completely. Soon after turning 42, Corke died of a rare, genetically inherited disorder called fatal familial insomnia (FFI). There’s no treatment or cure. Every patient diagnosed has died within ten months, some sooner. It’s taught us a shocking lesson: a lack of sleep will kill you.
The underlying cause of FFI is increasingly well understood. The culprit is an anomaly of a gene called PrNp, which stands for prion protein. All of us have prion proteins in our brain, and they perform useful functions. However, a rogue version of the protein is triggered by this genetic defect, resulting in a mutated version that spreads like a virus. In this genetically crooked form, the protein begins targeting and destroying certain parts of the brain, resulting in a rapidly accelerating form of brain degeneration as the protein spreads.
One region that this malfeasant protein attacks comprehensively is the thalamus — that sensory gate within the brain that must close for wakefulness to end and sleep to begin. When scientists performed postmortems of the brains of early FFI sufferers, they discovered a thalamus that was peppered with holes. The prion proteins had burrowed throughout the thalamus, utterly degrading its structural integrity. Due to this attack, the sensory gate of the thalamus was effectively stuck in a permanent ‘open’ position.”
Sleep & Light
“A hint of dim light — 8 to 10 lux — has been shown to delay the release of nighttime melatonin in humans. The feeblest of bedside lamps pumps out twice as much: 20–80 lux. A subtly lit living room, where most people reside in the hours before bed, will hum at around 200 lux. 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.
Blue LEDs, invented in 1997, offer considerable advantages over incandescent lamps in terms of lower energy demands and, for the lightbulbs, longer lifespans. But they may be inadvertently shortening our own. The light receptors in the eye that communicate ‘daytime’ to the suprachiasmatic nucleus are most sensitive to short-wavelength light within the blue spectrum — the exact sweet spot where blue LEDs are most powerful. As a consequence, evening blue LED light has twice the harmful impact on nighttime melatonin suppression than the warm, yellow light from old incadescent bulbs, even when their lux intensities are matched.”
Sleep & Alcohol
“Alcohol fragments sleep, littering the night with brief awakenings. Alcohol-infused sleep is therefore not continuous and, as a result, not restorative. Unfortunately, most of these nighttime awakenings go unnoticed by the sleeper since they don’t remember them. Individuals therefore fail to link alcohol consumption the night before with feelings of next-day exhaustion caused by the undetected sleep disruption sandwiched in between.
Second, alcohol is one of the most powerful suppressors of REM sleep that we know. 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. It’s rather like the cerebral version of cardiac arrest, preventing the pulsating beat of brainwaves that otherwise power dream sleep. People consuming even moderate amounts of alcohol in the afternoon and/or evening are thus depriving themselves of dream sleep.”
“You don’t have to be using alcohol to levels of abuse, however, to suffer its deleterious REM-sleep-disrupting consequences, as one study can attest. Recall that one function of REM sleep is to aid in memory integration and association: the type of information processing required for developing grammatical rules in new language learning, or in synthesizing large sets of related facts into an interconnected whole. To wit, researchers recruited a large group of college students for a 7-day study. The participants were then assigned to one of three experimental conditions. On day 1, all the participants learned a novel, artificial grammar, rather than like learning a new computer coding language or a new form of algebra. It was just the type of memory task that REM sleep is known to promote. Everyone learned the new material to a high degree of proficiency on that first day — around 90% accuracy. Then, a week later, participants were tested to see how much of that info had been solidified by the six nights of intervening sleep.
What distinguished the three groups was the type of sleep they had. In the first group — the control — participants were allowed to sleep fully for all intervening nights. In the second group, the experimenters got the students a little drunk just before bed on the first night after daytime learning. They loaded up the participants with 2–3 shots of vodka orange juice, standardizing the specific blood alcohol amount on the basis of gender and body weight. In the third group, they allowed the participants to sleep naturally on the first and even the second night after learning, and then got them similarly drunk before bed on night 3. (All three groups learned the material on day 1 and were tested while sober on day 7, so the experiment wasn’t testing the direct effects of alcohol on memory formation but the disruption of the memory facilitation that occurred in between.)
On day 7, participants in the control condition remembered everything they’d originally learned, even showing an enhancement of abstraction and retention of knowledge relative to initial levels of learning, just as we’d expect from good sleep. In contrast, those who’d had their sleep laced with alcohol on the first night forgot more than 50% 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.
The real surprise came in the results of the third group. Despite getting two full nights of sleep after initial learning, having their sleep doused with alcohol on the third night still resulted in almost the same degree of amnesia — 40% of the knowledge they’d worked so hard to establish on day 1 was forgotten.”
Sleep & Body Temp
“Sleep has not yet finished tending to those newly planted memories by night 3. The politically incorrect advice I’d give is this: go to the pub for a drink in the morning. That way, alcohol will be out of your system before sleep.”
“Once core temp dips below a threshold in the evening, the thermosensitive cells quickly deliver a message to the suprachiasmatic nucleus. The memo adds to that of naturally fading light, informing the suprachiasmatic nucleus to initiate the evening surge in melatonin, and with it, the timed ordering of 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 isn’t passive in letting the cool of night lull it into sleep, but actively participates. One way you control your core body temp is using the surface of your skin. Most of the thermic work is performed by three parts of your body in particular: your hands, feet, and head. All three areas are rich in crisscrossing blood vessels that lie close to the skin’s surface. Like stretching clothes over a drying line, this mass of vessels will allow blood to be spread across a large surface area of skin and come in close contact with the air that surrounds it. The hands, feet, and head are therefore remarkably efficient radiating devices that, just prior to sleep onset, jettison body heat in a massive thermal venting session so as to drop your core body temp. Warm hands and feet help your body’s core cool, inducing inviting sleep quickly and efficiently.”
“The need to dump heat from our extremities is also the reason that you may occasionally stick your hands and feet out from underneath the bedcovers at night due to your core becoming too hot. The limb rebellion aids in keeping the body core cool, allowing it to fall and stay asleep.
The coupled dependency between sleep and body cooling is evolutionarily linked to the 24-hour ebb and flow of daily temperature. Homo sapiens (and thus modern sleep patterns) evolved in the eastern equatorial regions of Africa. Despite experiencing only modest fluctuations in average temp across a year (+/- 5 degrees), these areas have larger temperature differentials across a day and night in both the winter and summer (+/- 13 degrees).
Pre-industrial cultures, such as the nomadic Gabra tribe in northern Kenya, ad the hunter-gatherers of the Hadza and San tribes, have remained in thermic harmony with this day-night cycle. They sleep in porous huts with no cooling or heating, minimal bedding, and lie semi-naked, from birth to death. Such willing exposure to ambient temp fluctuations is a major factor (alongside the lack of artificial evening light) determining their well-timed, healthy sleep quality. Without indoor-temp control, heavy bedding, or excess nighttime attire, they display a form of thermal liberalism that assists, rather than battles against, sleep’s conditional needs.
In stark contrast, industrialized cultures have severed their relationship with this natural rise and fall of environmental temperature. Through climate-controlled homes and the use of bedcovers and pajamas, we’ve architected a minimally varying thermal tenor in our bedrooms. Bereft of the natural drop in evening temp, our brains don’t receive the cooling instruction within the hypothalamus that facilitates a naturally timed release of melatonin. Moreover, our skin has difficulty ‘breathing out’ the heat it must in order to drop core body temp and make the transition to sleep, suffocated by the constant heat signal of controlled home temps. A bedroom temp of around 65 degrees is ideal for the sleep of most people, assuming standard clothing and bedding.”
“If you take a bath before night, you don’t fall asleep faster because you’re 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 temp plummets. Hot baths prior to bed can also induce 10–15% more deep NREM sleep in healthy adults.”
Alarms
“No other species demonstrates this unnatural act of prematurely and artificially terminating sleep (setting an alarm), and for good reason. Compare the physiological state of the body after being rudely awakened by an alarm to that observed after naturally waking from sleep. Participants artificially wrenched from sleep (like by an alarm) will suffer a spike in blood pressure and a shock acceleration in heart rate caused by an explosive burst of activity from the fight-or-flight branch of the nervous system.
Most of us are unaware of an even greater danger that lurks within the alarm clock: the snooze button. If alarming your heart, quite literally, were not bad enough, using the snooze feature means that you will repeatedly inflict that cardiovascular assault again and again within a short span of time. Step and repeat this 5+ days a week, and you begin to understand the multiplicative abuse your heart and nervous system will suffer across a lifespan. Waking up at the same time of day, every day, no matter if it’s the week or weekend is a good recommendation for maintaining a stable sleep schedule if you are having difficulty with sleep. Indeed, it’s one of the most consistent and effective ways of helping people with insomnia get better sleep. This unavoidably means the use of an alarm clock for many individuals. If you do use an alarm clcok, do away with the snooze function, and get in the habit of waking up only once to spare your heart the repeated shock.
A hobby of mine is to collect the most innovative (i.e. ludicrous) alarm clock designs in hope of cataloging the depraved ways we humans wrench our brains out of sleep. One such clock has a number of geometric blocks that sit in holes on a pad. When the alarm erupts in a blurting shriek in the morning, it also explodes the blocks out across the floor and won’t shut off the alarm until you pick up and reposition all of the blocks in their respective holes.
My favorite, however, is the shredder. You take a paper bill and slide it into the front of the clock at night. When the alarm goes off in the morning, you have a short amount of time to wake up and turn the alarm off before it begins shredding your money. A behavioral economist has suggested an even more fiendish system wherein your alarm is connected to your bank account. For every second you remain asleep, the alarm clock will send $10 to a political org…that you absolutely despise.”
Sleep Meds
“No past or current sleeping meds on the market induce natural sleep. The older sleep meds were blunt instruments. They sedated you rather than assisting you into sleep. Understandably, many people mistake the former for the latter. Most of the newer sleeping pills on the market present a similar situation, though they’re slightly less heavy in their sedating effects. Sleeping pills, old and new, target the same system in the brain that alcohol does — the receptors that stop your brain cells from firing — and are thus part of the same general class of drugs: sedatives. Sleeping pills effectively knock out the higher regions of your brain’s cortex.
If you compare natural, deep-sleep brainwave activity to that induced by modern-day sleeping pills, the electrical signature, or quality, is deficient. The electrical type of ‘sleep’ these drugs produce is lacking in the largest, deepest brainwaves. Adding to this state of affairs are a number of unwanted side effects, including next-day grogginess, daytime forgetfulness, performing actions at night you’re not conscious of, and slowed reaction times during the day that can impact motor skills like driving.
True even of the newer, shorter-acting sleeping pills on the market, these symptoms instigate a vicious cycle. The waking grogginess can lead people to reach for more cups of coffee to rev themselves up with caffeine throughout the day and evening. That caffeine, in turn, makes it harder for the individual to fall asleep at night, worsening the insomnia. In response, people often take an extra sleeping pill at night to combat the caffeine, but this only amplifies the next-day grogginess from the drug hangover. Even greater caffeine consumption then occurs, perpetuating the downward spiral.
Another deeply unpleasant feature of sleeping pills is rebound insomnia. When individuals stop taking these meds, they frequently suffer far worse sleep, sometimes even worse than the poor sleep that led them to seek out sleeping pills to begin with. The cause of rebound insomnia is a type of dependency in which the brain alters its balance of receptors as a reaction to the increased drug dose, trying to become somewhat less sensitive as a way of countering the foreign chemical within its brain. This is also known as drug tolerance. But when the drug is stopped, there’s a withdrawal process, part of which involves an unpleasant spike in insomnia severity.”
“The irony is that many individuals experience only a slight increase in ‘sleep’ from these meds, and the benefit is more subjective than objective. A recent team of researchers examined all published studies to date on newer forms of sedative sleeping pills that most people take, considering 65 separate drug-placebo studies of 4,500 individuals. Overall, participants subjectively felt they fell asleep faster and slept more soundly with fewer awakenings, relative to the placebo. But that’s not what the actual sleep recordings showed. There was no difference in how soundly the individuals slept. Both the placebo and the sleeping pills reduced the time it took people to fall asleep (between 10–30 minutes), but the change wasn’t statistically different between the two. In other words, there was no objective benefit of these sleeping pills beyond that which a placebo offered.
“In a study, sleeping pills caused a 50% weakening (unwiring) of the brain-cell connections originally formed during learning. Although users of sleeping pills may fall asleep nominally faster at night, they should expect to wake up with few(er) memories of yesterday. This is of special concern considering the average age for those receiving sleep med prescriptions is decreasing, as sleep complaints and incidents of pediatric insomnia increase. Young brains, which are still being wired up into the early 20s, will be attempting the already challenging task of neural development and learning under the subverting influence of prescription sleeping pills.
Even more concerning than brain rewiring are medical effects throughout the body that come with the use of sleeping pills — effects that aren’t widely known but should be. Most alarming is a discovery that individuals using sleep meds are significantly more likely to die and to develop cancer than those who don’t. In the early 2000s, insomnia rates ballooned and sleeping pill prescriptions escalated dramatically. It also meant much more data was available. And time and again, this same message emerged from the analyses.
So a researcher set up a well-controlled study that accounted for other factors and examined 10,000+ patients taking sleeping pills, contrasting them with 20,000 well-matched individuals who weren’t taking sleeping pills. Those taking sleeping pills were 4.6 times more likely to die over this short two-and-a-half-year period than those who weren’t using them. The risk of death scaled with the frequency of use. Heavy users, defined as taking more than 132 pills per year, were 5.3 times more likely to die over the study period than matched control participants who weren’t using sleeping pills.
More alarming was the mortality risk for people who only dabbled in sleeping pill use. Even those taking just 18 pills per year were still 3.6 times more likely to die during the two years than non-users. And there’s now more than 15 such studies from different groups showing higher rates of mortality from sleeping pills.
One frequent cause of sleeping pill mortality appears to be higher-than-normal rates of infection. Natural sleep is one of the most powerful boosters of the immune system, and it’s possible that medication-induced sleep doesn’t provide the same restorative benefits as natural sleep. This would be most troubling for the elderly, who are far more likely to suffer from infections and the heaviest users of sleeping pills.
Another cause of death linked to sleeping pill use is an increased risk for fatal car crashes, likely caused by the non-restorative sleep such drugs induce and/or the groggy hangover than some suffer, leaving individuals drowsy while driving the next day. Additional adverse associations in users of prescription sleeping pills included higher rates of heart disease and stroke.
Individuals taking sleeping pills were 30–40% more likely to develop cancer within the 2.5 years of the study than non-users.”
Behavioral Sleep Therapies
“The most effective treatment for insomnia is cognitive behavioral therapy for insomnia (CBT-I), and it’s rapidly being embraced as the first-time treatment. Working with a therapist for several weeks, participants are provided with a bespoke set of techniques intended to break bad sleep habits and address anxieties that have been inhibiting sleep. CBT-I builds on basic sleep hygiene principles, supplemented with methods individualized for the patient, their problems, and their lifestyle.
The most obvious methods include reducing caffeine and alcohol intake, remove screens 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 period; rather, get out of bed and do something quiet and relaxing until the urge to sleep returns, 4) avoid daytime napping, 5) reduce anxiety-provoking thoughts by learning to mentally decelerate before bed, and 6) remove visible clockface from view in the bedroom.
One of the more paradoxical CBT-I methods used to help insomniacs sleep is to restrict their time spent in bed, perhaps even to just six hours or less to begin with. By keeping patients awake longer, we build up a strong sleep pressure — a greater abundance of adenosine. Under this heaver weight of sleep pressure, patients fall asleep faster, and achieve a more stable, solid form of sleep across the night. In this way, a patient can regain their psychological confidence in being able to self-generate and sustain healthy, rapid, and sound sleep, something that’s eluded them for months or years. Upon establishing confidence, time in bed is gradually increased.
Results, which have been replicated in clinical studies around the globe, demonstrate that CBT-I is more effective than sleeping pills in addressing numerous problematic aspects of sleep for insomnia sufferers. 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. More importantly, the benefits of CBT-I persist long-term, even after patients stop working with their sleep therapist. This sustainability stands in stark contrast to the punch of rebound insomnia that individuals experience following the cessation of sleeping pills.”
Sleep and The Workplace
“A hundred years ago, less than 2% of the U.S. population slept six hours or less a night. Now, almost 30% of Americans do.”
“The lens of a 2013 survey by the National Sleep Foundation pulls this sleep deficiency into sharp focus. More than 65% of the U.S. adult population fails to obtain the recommended 7–9 hours of sleep each night during the week. Circumnavigate the globe, and things look no better. In the UK and Japan, for example, 39% and 66%, respectively, of all adults report sleeping fewer than seven hours. The WHO now labels the lack of societal sleep as a global health epidemic. Taken as a whole, one out of every two adults across all developed countries (about 800 million people) will not get the necessary sleep they need this coming week. Importantly, many of these individuals do not report wanting or needing less sleep.”
“A study across four large U.S. companies found that insufficient sleep cost almost $2k per employee per year in lost productivity. That amount rose to over $3,500 per employee in those suffering the most serious lack of sleep. This is a net capital loss to these companies of $54 million annually. Ask any board of directors whether they would like to correct a single problem fleecing their company of more than $50 million a year in lost revenue and the vote will be rapid and unanimous.”
“Why are individuals so financially ruinous to their companies, and national economies, when they’re under-slept? Employee traits that contribute to KPIs for companies are creativity, intelligence, motivation, effort, efficiency, effectiveness when working in groups, as well as emotional stability, sociability, and honesty. All of these are systematically dismantled by insufficient sleep.
Early studies demonstrated that shorter sleep amounts predict lower work rate and slow completion rate of basic tasks. That is, sleepy employees are unproductive employees. Sleep-deprived individuals also generate fewer and less accurate solutions to work-relevant problems they’re challenged with.”
“People often tell me that they don’t have enough time to sleep because they have so much work to do. 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 don’t get enough sleep at night.”
“Participants don’t perceive themselves as applying less effort to the work challenge, or being less effective, when they were sleep-deprived, despite both being true. They seemed unaware of their poorer work effort and performance. Even the simplest daily routines that require slight effort, such as time spent dressing neatly or fashionably for the workplace, have been found to decrease following a night of sleep loss. Individuals also like their jobs less when sleep deprived.
Under-slept employees are not only less productive, less motivated, less creative, less happy, and lazier, but they’re also more unethical. 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. Seminal work has found that the less an individual sleeps, the more likely they are to create fake receipts and reimbursement claims, and the more willing to lie to get free raffle tickets. Under-slept employees are more likely to blame other people for their own mistakes, and even try to take credit for other people’s successful work.
Ethical deviance linked to a lack of sleep also weasels its way onto the work stage in a different guise, called social loafing. The term refers to someone who, when group performance is being assessed, decides to exert less effort when working in that group than when working alone. Individuals see an opportunity to slack off and hide behind the collective hard work of others. They complete fewer aspects of the task themselves, and that work tends to be either wrong or of lower quality, relative to when they alone are being assessed. Not only does this lead to lower group productivity, understandably it often creates feelings of resentment and interpersonal aggression among team members.
Many of these studies report deleterious effects on business outcomes on the basis of only very modest reductions in sleep amount within an individual, perhaps 20- to 60-minute differences between an employee who’s honest, creative, innovative, collaborative, and productive and one who is not.”
“Examine the effects of sleep deficiency in CEOs and supervisors, and the story is equally impactful. An ineffective leader within an org can have manifold trickle-down consequences to the many whom they influence. We often think that a good or bad leader is good or bad day after day. Not true. Differences in individual leadership performance fluctuate dramatically from one day to the next, and the size of that difference far exceeds the average difference from one individual leader to another. The amount of sleep they’re getting is one clear reason why.
A deceptively simple but clever study tracked the sleep of supervisors across several weeks, and compared that with their leadership performance in the workplace as judged by employees who report to them. The lower the quality of sleep the supervisor reported getting from one night to the next accurately predicted poor self-control and a more abusive nature toward employees the following day, as reported by the employees themselves.
There was another equally intriguing result: in the days after a supervisor had slept poorly, the employees themselves, even if well rested, became less engaged in their jobs throughout the day. It was a chain-reaction effect, one in which the lack of sleep in that one superordinate person in a business structure was transmitted on like a virus, infecting even well-rested employees with work disengagement and reduced productivity.”
Sleep and School
“More than 80% of U.S. public high schools begin before 8:15am. Almost 50% of those start before 7:20am. School buses for a 7:20am start time usually begin picking up kids at 5:45am. As a result, some children and teenagers must wake up at 5:30am, 5:15am, or even earlier, and do so five days out of every seven, for years on end. This is lunacy.
5:15am to a teenager is not the same as 5:15am to an adult. The circadian rhythms of teenagers shifts forward dramatically by 1–3 hours. Could you concentrate and learn anything after having forcefully been woken up at 3:15am, day after day after day? Would you be in a cheerful mood? Why, then, do we ask this of the millions of teens and children in industrialized nations? Surely this isn’t an optimal design of education.
Forced by the hand of early start times, this state of chronic sleep deprivation is especially concerning considering that adolescence is the most susceptible phase of life for developing chronic mental illnesses, such as depression, anxiety, schizophrenia, and suicidality. Unnecessarily bankrupting the sleep of a teen could make all the difference in the precarious tipping point between wellness and lifelong psychiatric illness. Back in the 60s, when the functions of sleep were still largely unknown, researchers selectively depraved young adults of REM sleep, and thus dreaming, for a week, while still allowing them NREM sleep.
The unfortunate study participants spent the entire time in the lab with electrodes on their heads. At night, whenever they entered into the REM-sleep state, a research assistant would wake them up. The blurry-eyed participants then had to do math for 5–10 minutes, preventing them from falling back into dream sleep. But as soon as they did return to REM, the procedure was repeated — hour after hour for an entire week. NREM sleep was left largely intact, but the amount of REM sleep was reduced to a fraction of its regular quantity.
By the third day, the participants were expressing signs of psychosis. They became anxious, moody, and started to hallucinate. They were hearing and seeing things that weren’t real. They also became paranoid. Some believed that the researchers were plotting against them — trying to poison them, for example. Others became convinced that the scientists were secret agents, and that the study was a government conspiracy.
Only then did scientists realize the rather profound conclusions of the experiment: REM sleep is what stands between rationality and insanity. Describe these symptoms to a psychiatrist, and the clinician will give clear diagnoses of depression, anxiety disorders, and schizophrenia. But these were all healthy young individuals just days before. Any attempts to break sleep-deprivation world records throughout early history have the same universal signature of emotional instability and psychosis of one sort or another. It’s the lack of REM sleep — that critical stage occurring in the final hours of sleep that we strip from our children and teens by way of early start times — that creates the difference between a stable and unstable mental state.”
“Our children didn’t always go to school at this biologically unreasonable time. A century ago, U.S. schools started at 9am. As a result, 95% of all children woke up without an alarm. Now, the inverse is true.
A seminal scientist in the 20s found that no matter what the age, the longer a child slept, the more intellectually gifted they were. He further found that sleep time was most strongly connected to a reasonable (i.e. later) school start time: one that was in harmony with the innate biological rhythms of these young, still-maturing brains.”
“One longitudinal study tracked more than 5k Japanese schoolchildren and discovered that those individuals who were sleeping longer obtained better grades across the board. Controlled sleep lab studies in smaller samples show that children with longer total sleep times develop superior IQ, with brighter children having consistently slept 40–50 minutes more than those who went on to develop a lower IQ.
In a study started by Dr. Ronald Wilson in the 80s, which continues to this day, hundreds of twin pairs were assessed at a very young age. The researchers specifically focused on those twins in which one was routinely obtaining less sleep than the other, and tracked their developmental progress over the following decades. By ten years old, the twin with the longer sleep pattern was superior in their intellectual and educational abilities, with higher scores on standardized reading tests, and a more expansive vocabulary than the twin who was obtaining less sleep.”
“If sleep really is so rudimentary to learning, then increasing sleep time by delaying start times should prove transformative. It has.
A growing number of U.S. schools have started to revolt against the early start time model, beginning at more biologically reasonable times. One of the first test cases was in Edith, Minnesota. Here, school start times for teens were shifted from 7:25 to 8:30. More striking than the 43 minutes of extra sleep that these teens reported getting was the change in academic performance. In the year before the time change, the average verbal SAT scores of the top-performing students was 605. The following year, after switching to an 8:30 start time, that score rose to an average 761 for the same top-tier bracket of students. Math SAT scores also improved, increasing from an average of 683 in the year prior to the time change, to 739 in the year after. Investing in delaying school start times returned a net SAT profit of 212 points. That improvement will change which tier of university those teens go to, potentially altering their subsequent life trajectories as a consequence.”
“Numerous counties in several states have shifted to a later start time, and their students experienced significantly higher GPAs. Unsurprisingly, performance improvements were observed regardless of time of day; however, the most dramatic surges occurred in morning classes.
It’s clear that an under-slept brain is little more than a leaky memory sieve, in no state to receive, absorb, or efficiently retain an education. To persist in this way is to handicap our children with partial amnesia. We’re creating a generation of disadvantaged children, hamstrung by a privation of sleep.”
“Children from lower socioeconomic backgrounds are less likely to be taken to school in a car, in part because their parents often have jobs in the service industry demanding work start times at or before 6am. Such children therefore rely on school buses and must wake up earlier than those taken to school by their parents. As a result, those already disadvantaged children become even more so because they routinely obtain less sleep than children from more affluent families. The upshot is a vicious cycle that perpetuates from one generation to the next. We desperately need active intervention methods to shatter this cycle, and soon.”
“Research findings have also revealed that increasing sleep by way of delayed start times wonderfully increases class attendance, reduces behavioral and psychological problems, and decreases substance and alcohol use. In addition, later start times beneficially mean a later finish time. This protects many teens from the well-researched ‘danger window’ between 3pm and 6pm, when schools finish but before parents return home. This unsupervised, vulnerable time period is a recognized cause of involvement in crime and alcohol and substance abuse. Later school start times profitably shorten this danger window, reduce these adverse outcomes, and therefore lower the associated financial cost to society (a savings that could be reinvested to offset any additional expenditures that later school start times require).
“When the Mahtomedia School District of Minnesota pushed their school start times from 7:30 to 8, there was a 60% reduction in traffic crashes in drivers 16–18 years old. Teton County in Wyoming shifted from a 7:35 bell to an 8:55 one. The result was astonishing — a 70% reduction in traffic crashes in 16–18 year old drivers.
To place that in contest, the advent of anti-lock brakes (ABS) — which prevents the wheels of a car from seizing up under hard braking, allowing the driver to still maneuver the vehicle — reduced crash rates by 20–25%. It was deemed a revolution. Here’s a simple biological factor — sufficient sleep — that will drop crash rates by more than double that amount in teens.
These publicly available findings have largely been swept under the rug. Change has been slow and hard-fought. It is not enough.”
“Without change, we will simply perpetuate a vicious cycle wherein each generation of our children are stumbling through the education system in a half-comatose state, chronically sleep-deprived for years on end, stunted in their mental and physical growth as a consequence, and failing to maximize their true success potential, only to inflict that same assault on their own children decades later. This harmful spiral is only getting worse. Data aggregated over the past century from 750,000+ schoolchildren aged 5–18 reveal that they’re sleeping two hours fewer per night than their counterparts were 100 years ago. This is true no matter what age group, or sub age group, you consider.”
“An added reason for making sleep a priority concerns the link between sleep deficiency and ADHD. Children with this diagnosis are irritable, moodier, more distractible and unfocused in learning during the day, and have a significantly increase prevalance of depression and suicidal ideation. If you make a composite of these symptoms (unable to maintain focus and attention, deficient learning, behaviorally difficult, with mental health instability), and then strip away the label of ADHD, these symptoms are nearly identical to those caused by a lack of sleep. Take an under-slept child to a doctor and describe these symptoms without mentioning the lack of sleep, which isn’t uncommon, and what would you imagine the doctor is diagnosing and medicating the child for? Not deficient sleep, but ADHD.”
“We estimate that 50%+ of all children with an ADHD diagnosis actually have a sleep disorder, yet a small fraction know of their sleep condition and its ramifications. A major public awareness campaign by governments is needed.”
Sleep & Medicine
“If you’re about to receive medical treatment at a hospital, you’d be well-advised to ask the doctor: ‘How much sleep have you had in the past 24 hours?’ The doctor’s response will determine, to a statistically provable degree, whether treatment you receive will result in a serious medical error, or even death.”
“All of us know that nurses and doctors work long, consecutive hours, and none more so than doctors during their resident training years. Why did we ever force doctors to learn their profession in this exhausting, sleepless way? The answer originated with the esteemed physician William Halsted, who was also a helpless drug addict.
Halsted founded the surgical training program at Johns Hopkins in 1889. His influence was considerable, and his beliefs about how young doctors must apply themselves to medicine, formidable. There was to be a six-year residency, quite literally. The term ‘residency’ came form 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 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 dirty secret that only come 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.”
“Many med schools used to require residents work 30 hours all in one go. Worse, they often had to do two of these 30-hour continuous shifts within a week, combined with several 12-hour shifts scattered in between.
The injurious consequences are well-documented. Residents working a 30-hour-straight shift will commit 36% more serious medical errors, such as prescribing the wrong dose of a drug or leaving a surgical implement inside of a patient, compared with those working 16 hours or less. Additionally, after a 30-hour shift without sleep, residents make a whopping 460% more diagnostic mistakes in the intensive care unit than when well rested after enough sleep. Throughout the course of their residency, 1 in 5 medical residents will make a sleepless-related medical error than causes significant, liable harm to a patient. One in 20 residents will kill a patient due to a lack of sleep. Since there’s 100,000+ residents currently in training in the U.S., that means that many hundreds of people are losing their lives every year because residents aren’t allowed to get the sleep they need. Medical errors are the third-leading cause of death among Americans after heart attacks and cancer. Sleeplessness undoubtedly plays a role in those lives lost.”
“When a sleep-deprived resident finishes a long shift, their chances of being involved in a car crash are increased by 168% because of fatigue. As a result, they may find themselves back in the very same hospital and ER from which they departed.”
“If you’re a patient under the knife of an attending physician who hasn’t been allowed at least a six-hour sleep opportunity the night prior, there’s a 170% increased risk of that surgeon inflicting a serious surgical error on you. If you’re about to undergo an elective surgery, you should ask how much sleep your doctor has had, and if it’s not to your liking, you may not want to proceed.”
Sleep & Society
“Consider the infamous reactor meltdown at the Chernobyl nuclear power station on April 26, 1986. The radiation from the disaster was 100 times more powerful than the atomic bombs dropped in WWII. It was the fault of sleep-deprived operators working an exhaustive shift, occurring, without coincidence, at 1am. Thousands died from the long-term effects of radiation in the protracted decades following the event, and tens of thousands more suffered a lifetime of debilitating medial and development ill health.”
“We can also recount the Exxon Valdez oil tanker that ran aground in Alaska on March 24, 1989, breaching its hull. An estimated 10–40 million gallons of crude oil spilled across a 1,300-mile range of the surrounding shoreline. Left dead were more than 500,000 seabirds, 5,000 otters, 300 seals, 200+ bald eagles, and 20 orca whales. The coastal ecosystem has never recovered. It was revealed that the captain had turned over command to his third mate on deck, who’d slept only six out of the previous 48 hours, causing him to make the cataclysmic navigational error.”
Sleep Tech
“Devices could compare the sleep of each family member in each separate bedroom with the temperature sensed in each room by thermostat. Using common machine-learning algorithms applied over time, we should be ale to intelligently teach the home thermostat what the thermal sweet spot is for each occupant in each room, based on the biophysiology calculated by their sleep-tracking device (perhaps splitting the difference when there’s 2+ individuals in a room).
Better still, we could program a natural circadian lull and rise in temperature across the night that’s in harmony with each body’s expectations, rather than the constant nighttime temp set in most homes. Over time, we could intelligently curate a tailored thermal sleep environment that’s personalized to the circadian rhythms of each individual occupant of each bedroom. Both of these changes require no effort from an individual, and should hasten the speed of sleep onset, increase total sleep time, and even deepen NREM sleep quality.”
“Soon, we should be able to engineer LED bulbs with filters that can vary the wavelength of light that they emit, ranging from warm yellow colors less harmful to melatonin, to strong blue light that powerfully suppresses it.
Paired with sleep trackers that accurately characterize our personal biological rhythms, we can connect these new bulbs to the home network. They would be instructed to gradually dial down the harmful blue light in the home as the evening progresses, based on an individual’s natural sleep-wake pattern. We could do this seamlessly as individuals move from one room to another.
Come morning, we can reverse this trick. We can now saturate our indoor environments with powerful blue light that shuts off any lingering melatonin. This will help wake us up faster, more alert, and with a brighter mood.
We could even use this light-manipulation idea to apply a slight nudge in someone’s sleep-wake rhythm within a biologically reasonable range (+/- 30–40 minutes), should they desire, gradually moving it earlier or later. For example, if you have an unusually early meeting in the middle of a workweek, this tech, synched to your calendar, would gradually begin shifting you (your circadian rhythm) to a slightly earlier bed and rise time starting on Monday. This way, that early-morning rise on Wednesday won’t be as miserable, or cause such biological turmoil within your brain and body. This would be equally applicable in helping individuals overcome jet lag.
Cars can adopt these same lighting solutions to help manipulate alertness during morning commutes, which have some of the highest drowsy-driving crash rates. What if car cockpits could be bathed in blue light during early morning drives? In the workplace, for those lucky enough to have their own office, lighting rhythm could be custom fit to the occupant. But even cubicles could be personally tailored in this light-dependent manner based on the individual in them.”
Sleep & Space
“Astronauts on the International Sleep Station travel through space at 17,500 miles per hour and complete an orbit of Earth once every 90–100 minutes. As a result, they experience ‘daylight’ for about 50 minutes, and ‘night’ for about 50 minutes. Although astronauts are therefore treated to the delight of a sunrise and sunlight 16 times a day, it wreaks utter havoc on their sleep-wake rhythms, causing insomnia and sleeplessness. To combat this issue, NASA began collaborating with an electrical company to create bulbs to bathe the astronauts in a much more Earth-like cycle of 24-hour light and dark. With regulated environmental light came a superior regulation of the astronauts’ biological melatonin rhythms, including their sleep, thereby reducing operations errors associated with fatigue.”
Sleep Education & Change
“When I asked a diverse set of individuals if they’d received any education about sleep, 0% said they’d received any. If these individuals are representative, it suggests that sleep holds no place in the education of our children. Generation after generation, our young minds continue to remain unaware of the immediate dangers and protracted health impacts of insufficient sleep. I would be keen to develop a simple educational module that can be implemented in schools around the world. It could be an animated short online, a board game, or a virtual environment that helps you explore the secrets of sleep.”
“Aetna, which has almost 50,000 employees, has instituted the option of bonuses for getting more sleep, based on sleep tracker data. Workers must string together 20 seven-hour nights of sleep or more in a row to qualify.”
“Pain-related centers within the human brain are 42% more sensitive to unpleasant thermal stimulation following a night of sleep deprivation. These pain-related regions are the same areas that narcotics, such as morphine, act upon. Sleep appears to be a natural analgesic, and without it, pain is perceived more acutely by the brain. Morphine has serious safety issues related to the cessation of breathing, dependency, and withdrawal, together with terribly unpleasant side effects like nausea and urinary issues, not to mention a form of sedation that prevents natural sleep. Morphine also alters the action of other meds, resulting in problematic interaction effects.
Extrapolating from a now extensive set of scientific research, we should be able to reduce the dose of narcotics on our hospital wards by improving sleep conditions. In turn, this would lessen safety risks, reduce side effects, and decrease the potential for drug interactions.
Improving sleep conditions would also boost patients’ immune systems. Inpatients could therefore mount a far more effective battle against infection and accelerate postop wound healing.”
