Why We Sleep

May 1

Description

Matthew Walker has made abundantly clear that sleep is one of the most important but least understood aspects of our life. Until very recently, science had no answer to the question of why we sleep, or what good it served, or why we suffer such devastating health consequences when it is absent. Compared to the other basic drives in life—eating, drinking, and reproducing—the purpose of sleep remains more elusive.

Within the brain, sleep enriches a diversity of functions, including our ability to learn, memorize, and make logical decisions. It recalibrates our emotions, restocks our immune system, fine-tunes our metabolism, and regulates our appetite. Dreaming creates a virtual reality space in which the brain melds past and present knowledge, inspiring creativity.

In Why We Sleep, preeminent neuroscientist, former professor at Harvard, and sleep expert Matthew Walker provides a revolutionary exploration of sleep, examining how it affects every aspect of our physical and mental well-being. Charting the most cutting-edge scientific breakthroughs, and marshaling his decades of research and clinical practice, Walker explains how we can harness sleep to improve learning, mood and energy levels, regulate hormones, prevent cancer, Alzheimer’s and diabetes, slow the effects of aging, and increase longevity. He also provides actionable steps towards getting a better night’s sleep every night.

The Book In 3 Sentences

Sleep is not just a pillar of good health, but it is the foundation that diet, exercise, and mental health rest on. The physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise. Sleep is the single most effective thing we can do to reset our brain and body health each day.
Dreams deliver real benefits. REM-sleep and dreams help reduce the pain from traumatic events, help us decode facial expressions accurately, and improve problem-solving and creativity. Plus sleeping frees up space for new memories and helps us remember new information. Sleep before learning something new refreshes our ability to initially make new memories. Sleep after learning something new enhances memory retention.
The shorter you sleep, the shorter your life span. Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer. Even moderate reductions for just one week of inadequate sleep disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic. Sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety, and suicidality. Not convinced yet, here is the big one — insufficient sleep is a key lifestyle factor determining whether or not you will develop Alzheimer’s disease.

Who Should Read It?

Before we go further, quick check-in for those of you who may think you can get by on less than the recommended (7-9) hours of sleep: The odds that you fall into the bucket of people who can truly thrive on less sleep are incredibly low. “It is far, far more likely that you will be struck by lightning (the lifetime odds being 1 in 12,000) than being truly capable of surviving on insufficient sleep thanks to a rare gene.” (As Matthew says, round the odds down to the nearest whole integer and the odds of you being able to get away with less sleep are, effectively, ZERO. :)

In case you didn’t know why sleep was important, this book makes the data clear – sleep is vital to our health and has the ability to make us smarter, more attractive, live longer, slimmer, and happier. Why We Sleep convinced me sleep is a huge advantage in life, and is likely going to convince you of the same.

Are there days when you don't have a clear mind? Are you sometimes forgetful? Are you sometimes less optimistic than you used to be? How patient are you? Do you feel you're not performing well enough at sports? Do you sometimes feel dizzy? Do you have headaches? Why do you think that is? Are you having too much coffee? Are you having too little? Maybe you have high blood pressure? Or low?

Well, there could be a much simpler explanation. As Walker puts it, you could be sleep-deprived — lots of people are and many don't even know.

Plus, in Why We Sleep Walker backs everything up with a summary of all the scientific research on sleep to date, providing insight on how sleep affects cognitive and physical performance in both the short and long term, and what you can do improve your own sleep (which often involves avoiding things causing bad sleep).

Recommended for everyone, as sleep affects us all! Why We Sleep should be required reading for everyone.

How The Book Changed Me

Why We Sleep is one of the most important books I’ve ever read. It has been a huge eye-opener for me.

Tons of CEOs, entrepreneurs, leaders, etc. all have a very open mentality on sleep: “You’ll have a chance to sleep when you’re dead.” Heard of that one before?

How about, “Six hours of sleep is enough for a functional adult.”, or your friend saying “(insert famous name) sleeps only four hours/day, so I should do the same to be like them.”

It has been imprinted on us that those who sleep a lot are lazy, unproductive, and never going to amount to much. It is a ‘bad habit’. Successful people are busy working round the clock, not sleeping.

If you read Why We Sleep (and you should; whether you love, hate, enjoy, avoid, or have a problem with sleeping) you'd understand why the evolutionary process didn't eliminate sleep from our biology. Instead, it has only become more important! By sleeping more, you are doing the best thing possible for your cognitive and physical health!

Even if you feel sleep is unnecessary, time-wasting, futile, and unproductive, you still need to get a good night's sleep to get a long list of physiological, biological, psychological benefits.

And from reading this book I’ve learned that, by any chance, you fail to get the necessary amount of sleep (voluntarily or otherwise), you're a big gambler who doesn't have the idea about the grave repercussions. (No kidding.)

Since reading Why We Sleep, I’ve given myself a non-negotiable minimum of 8 hours of sleep a day, and aim to sleep 9.5 hours each night.

An interesting thing I learned is that people confuse time slept with sleep opportunity time. Most people give themselves 6.5 hours of sleep opportunity (time in bed), which normally means they will only obtain around 5 hours of actual sleep. So Walker tells us to keep a buffer of 1.5 hours to make up for actual time asleep.

That way even at 8 hours of time in bed for me, I am getting at least 6.5 hours of time asleep. (Anything under 6 hours and you are clinically sleep deprived).

Besides this, Walker gives us many tips in Why We Sleep on how to improve our ‘sleep hygiene,’ such as reducing exposure to electronics emitting blue lights before bed, which temperature to keep the room at night, strategies for insomniacs, etc. and I try to include most of his tips in my evening routine.

My Rating

I gave Why We Sleep a 9/10 because I feel like it truly changed my life. I know that is a cliché thing to say — but it is true for this book!

We often are so caught up in learning tricks, information, knowledge that will improve our life by 10% and debate with our friends about if the keto diet is better than the paleo diet. But sleep? Sleep is more than one-third of our lives and NO ONE talks about it! If they do, it’s as a joke while getting their fourth cup of coffee and laughing about how they barely slept last night.

Why We Sleep just lays it out all in plain sight, backed by science. Why do we sleep? Why do we dream? Why sometimes we can’t sleep? Do insects sleep, and why? Etc. And of course, it shows you the dark side of not getting enough sleep.

Where I felt it loses a couple of points is that, well, the book is not fun to read.

Just being honest here!

Like yes, it was interesting and Why We Sleep was VERY life-changing, but gosh it was such a dry read. Even with a background in neuroscience, I was finding myself bored. And I know, while non-fiction books are not meant to be entertaining, there were times I was telling myself to, ‘just get through the chapter,’ so I could finish the book.

But if you can get through that, Why We Sleep is worth its weight in gold! I feel so much smarter and well-informed about something we do every single day. And truly, reading Why We Sleep might’ve added at least 10 more years to my life.

My Top 3 Quotes

"Sleep loss inflicts such devastating effects on the brain, linking it to numerous neurological and psychiatric conditions (e.g., Alzheimer’s disease, anxiety, depression, bipolar disorder, suicide, stroke, and chronic pain), and on every physiological system of the body, further contributing to countless disorders and disease (e.g., cancer, diabetes, heart attacks, infertility, weight gain, obesity, and immune deficiency). No facet of the human body is spared the crippling, noxious harm of sleep loss." ― Matthew Walker, PhD, Why We Sleep
“The problem is that some people confuse time slept with sleep opportunity time. We know that many individuals in the modern world only give themselves 5 to 6.5 hours of sleep opportunity, which normally means they will only obtain around 4.5 to 6 hours of actual sleep.” ― Matthew Walker, PhD, Why We Sleep
“Asking your teenage son or daughter to go to bed and fall asleep at ten p.m. is the circadian equivalent of asking you, their parent, to go to sleep at seven or eight p.m. 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 four or five a.m.” ― Matthew Walker, PhD, Why We Sleep

Bonus:

“I was once fond of saying, ‘Sleep is the third pillar of good health, alongside diet and exercise.’ I have changed my tune. Sleep is more than a pillar; it is the foundation on which the other two health bastions sit. Take away the bedrock of sleep, or weaken it just a little, and careful eating or physical exercise become less than effective, as we shall see.” ― Matthew Walker, PhD, Why We Sleep

Best Big Ideas

Please Note: The following is a collection of highlights taken straight from the book and online resources. Most of them are direct quotes. Some are paraphrases. Very few are my own words.

Sleep Is Universal

Theodosius Dobzhansky once said, ‘nothing in biology makes sense except in the light of evolution.’ For sleep, the illuminating answer turned out to be far earlier than anyone anticipated, and far more profound in ramification.

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 larger sharks; amphibians, such as frogs; and reptiles, such as turtles, Komodo dragons, and chameleons. All have a bona fide sleep. Ascend the evolutionary ladder further and we find all types of birds and mammals sleep: from shrews to parrots, kangaroos, polar bears, bats, and, of course, we humans. Sleep is universal.

We’d be wise to remember that anything THAT universal MUST have an incredibly strong evolutionary reason for its existence. Violate millions of years of evolution at your own risk!

Amazing Breakthrough!

Scientists have discovered a revolutionary new treatment that makes you live longer. It enhances your memory and makes you more creative. It makes you look more attractive. It keeps you slim and lowers food cravings. It protects you from cancer and dementia. It wards off colds and the flu. It lowers your risk of heart attacks and strokes, not to mention diabetes. You’ll even feel happier, less depressed, and less anxious. Are you interested?

While it may sound hyperbolic, nothing about this fictitious advertisement would be inaccurate. If this were a drug, many people will be disbelieving. Those who were convinced would pay large sums of money for even the smallest dose. Should clinical trials back up the claims, share prices of the pharmaceutical company that invented the drug would skyrocket.

Of course, the ad is not describing some miracle new tincture or a cure-all wonder drug, but rather the proven benefits of a full night of sleep. The evidence supporting these claims have been documented in more than 17,000 well-scrutinized and scientific reports to date. As for the prescription cost, well, there isn’t one. It’s free. Yet all too often, we shun the nightly invitations to receive our full dose of this all natural remedy–with terrible consequences.

Failed by the lack of public education, most of us do not realize how remarkable a panacea sleep truly is.

P.S. Actual sleeping pills? Walker dedicates a chapter to outlining why they are a REALLY bad idea. They don’t help induce real, restorative sleep. They merely sedate us (think of a coma) so we miss out on all the benefits of sleep. Science says CBT-I is a much better option!

Time Asleep vs Sleep Opportunity

The problem is that some people confuse time slept with sleep opportunity time. We know that many individuals in the modern world only give themselves 5 to 6.5 hours of sleep opportunity, which normally means they will only obtain around 4.5 to 6 hours of actual sleep.

As a rule of thumb, add 1.5 hours to how much sleep you want to account for time in bed. This will include the time it takes to go to sleep, if you wake up in the middle of the night to use the bathroom or drink water, and periods when you switch through sleep cycles or wake up in the middle of the night.

P.S. Anything under 6 hours of sleep (hence 7.5 hours of time in bed) means you are clinically sleep deprived.

Does Melatonin Actually Help? What About Caffeine?

Your circadian rhythm is one of two factors determining wake and sleep. Melatonin helps regulate the timing of when sleep occurs by signaling darkness throughout the organism but has little influence on the generation of sleep itself.

Sleep pressure, caused by a buildup of the chemical adenosine in your brain, is the second-factor affecting sleepiness. Caffeine works by blocking the receptors that adenosine effects (after about 30 minutes).

Caffeine temporarily blunts the feeling of adenosine, but not the accumulation of it. This is why, once the liver flushes out the caffeine, you experience a crash because you feel the effects of all that built up adenosine at once.

Night Owl or Morning Larks — Fake news?

Not so much, turns out that everyone has a different circadian rhythm built in their DNA.

For some people, their peak of wakefulness arrives early in the day, and their sleepiness trough arrives early at night. These are “morning types,” and make up about 40% of the population. These people tend to wake around dawn and are happy to do so and function optimally at this time of day.

Other people are “evening types” and account for about 30% of the population. These people prefer going to bed late and wake up late the following morning. The remaining 30% of the population is somewhere between a morning and evening type.

Your “type,” i.e. whether you’re a morning or evening person, is known as your chronotype and it’s largely determined by genetics. If you’re a night owl, it’s likely that one or both of your parents is a night owl. To find your chronotype, take this quiz.

Sadly, society treats night owls as lazy since they don’t like to wake up until later in the morning. In addition, society’s work schedule favors morning types. Evening types are often forced into an unnatural sleep-wake rhythm to meet a certain work schedule, thus evening types are more often sleep-deprived.

You may be wondering why Mother Nature would program this variability across people. As a social species, should we not all be synchronized and therefore awake at the same time to promote maximal human interactions? Perhaps not. Humans likely evolved to co-sleep as families or even whole tribes, not alone or as couples.

Because of this, the benefits of such genetically programmed variation in sleep/wake timing preferences can be understood.

The night owls in the group would not be doing to sleep until one or two a.m. , and not waking until nine or ten a.m. The morning larks, on the other hand, would have retired for the night at nine p.m. and woken at five a.m. Consequently, the group as a whole is only collectively vulnerable (i.e., every person asleep) for just four rather than eight hours, despite everyone still getting the chance for eight hours of sleep. That’s potentially a 50 percent increase in survival fitness.

Truly Wild Stats

Why We Sleep is filled with RIDICULOUSLY compelling stats to take sleep seriously. That might just be the most compelling.

Often, a single astonishing result is all the people need to apprehend the point. For cardiovascular health, I believe that finding comes from a ‘global experiment’ in which 1.5 billion people are forced to reduce their sleep by one hour or less for a single night each year. It is very likely that you have been part of this experiment, otherwise known as daylight savings time.

In the Northern Hemisphere, the switch to daylight savings time 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 accidents, proving that the brain, by way of attention lapses and micro-sleeps, 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.

Dreaming as Overnight Therapy

During REM sleep, and dreaming specifically, the brain starts to combine information. Your dreams are a compound of what you’ve recently learned and a back catalog of autobiographical information that you’ve got stored in your brain. Based on the act of combining these areas of information, your brain starts to build novel connections.

Walker describes REM as being like group therapy for memories. Through this pattern of informational alchemy at night, we create a revised mind wide web of associations.

In your waking life, these associations can kickstart novel insights that can help solve problems. This is why you may have experienced waking up to new solutions.

No wonder the saying isn’t “Stay awake on a problem.” Instead, people tell you to sleep on a problem. This saying is now supported by substantial evidence.

REM sleep is essentially a form of overnight therapy. It’s during dream sleep we can take the sting out of difficult, even traumatic, emotional experiences.

Sleep almost removes that emotional, bitter rind from the memorable experiences we’ve had during the day. Hence, we can wake up the next morning feeling better about those experiences.

Based on this, Walker suggests you think of dream sleep as emotional first aid. Dream sleep offers a nocturnal balm that soothes the painful stinging edges of challenging experiences.

So, it’s not just time that heals all wounds. Instead, it’s time spent in dream sleep that provides you with emotional healing.

Is Sleep Debt Real?

Sleep is not like a bank. You can’t accumulate a debt and then hope to pay it off at some later point in time.

Instead, sleep is an all-or-nothing event.

You can’t skip sleep during the week and then try to binge and oversleep at the weekend. This sleep binge will not make up for your previous lost sleep.

Human beings are the only species that deliberately deprive themselves of sleep. Hence, Mother Nature has never had to face the challenge of sleep deprivation during the course of evolution. Subsequently, humans have not evolved a safety net mechanism that overcomes sleep debt.

Electronics Are Kryptonite For Sleep (THe iPad Effect)

A recent survey of over fifteen hundred American adults found that 90 percent of individuals regularly used some form of portable electronic device 60 minutes or less before bedtime. It has a very real impact on your melatonin release, and thus ability to time the onset of sleep.

One of the earliest studies found that using an iPad–an electronic tablet enriched with blue LED light–for two hours prior to bed blocked the otherwise rising levels of melatonin by a significant 23 percent.

More recent research goes several concerning steps further. Healthy adults lived for a two-week period in a tightly controlled laboratory environment. The two-week period was split in half, containing two different experimental arms that everyone passed through: (1) five nights of reading a book on an iPad for several hours before bed (no other iPad uses, such as email or Internet, were allowed), and (2) five nights of reading a printed paper book for several hours before bed, with the two conditions randomized in terms of which the participants experience first or second.

Compared to reading a printed book reading on an iPad suppressed melatonin released by over 50% at night. Indeed, iPad reading delayed the rise of melatonin by up to three hours, relative to the natural rising the same individuals experience when reading a printed book.

When reading on the iPad, their melatonin peak, and thus instruction to sleep, did not occur until the early morning hours, rather than before midnight. Unsurprisingly, individuals took longer to fall asleep after iPad reading relative to print-copy reading.

Sid Chawla

“I've had a lot of worries in my life, most of which never happened.” - Mark Twain