Otis Chandler's Reviews > Why We Sleep: Unlocking the Power of Sleep and Dreams

Why We Sleep by Matthew Walker
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it was amazing
bookshelves: nonfiction, self-improvement, science, health

The author, Matthew Walker, makes a compelling case for sleep that frankly even after having read many articles about the importance of sleep, and even watching his TED talk, changed my perspective. It has convinced me that I have likely been under-slept much of the past 10 years (3 kids and a busy job will make it hard), and that has been a negative contributor to my health and well being. Specifically, I have always been of the belief that I am a person who can subsist on 6-7 hours of sleep, but this book makes me believe I need to be getting 8, and that the difference is material to both my mental and physical health.

"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 twenty-four hours."

But more so, it warns of a global sleep epidemic. And this really rings true. Sleep is something we spend (if we are doing it right), a third of our lives doing, and which should be put up there with eating well and exercising. And yet how often have you heard recommendations for eating well and exercising that don't also include a recommendation to sleep enough? The book makes a strong case that we are vastly under educating people about the benefits of sleep. This sentence for instance, both rings true and is one of the scariest in the book:

"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 latter is rarely made in their 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."

If this isn't an epidemic, what is? Like me, many of us have a notion that we should work hard during the week and "catch up" later or (pre-kids) on the weekend. Interestingly, this notion is false - we can never catch up, the damage has been done.

"More than 65 percent of the US adult population fail to obtain the recommended seven to nine hours of sleep each night during the week."

It's not just our culture of working too hard and looking at screens too much, there are a few specific cultural things the book rants against. First (and in my opinion, justified) is a rant against schools that have start times that are too early - teenagers in particular still have forming brains and need their sleep. Second and most ironic is our medical schools culture of 24 or 48 hour shifts - the medical community should know better, and if they don't, it's no wonder the rest of us don't take it seriously enough.

Unnecessarily bankrupting the sleep of a teenager could make all the difference in the precarious tipping point between psychological wellness and lifelong psychiatric illness. This is a strong statement, and I do not write it flippantly or without evidence."

I used to go to Terman Library all the time - and as a parent this was fascinating:

"The Stanford psychologist Dr. Lewis Terman, famous for helping construct the IQ test, dedicated his research career to the betterment of children’s education. Starting in the 1920s, Terman charted all manner of factors that promoted a child’s intellectual success. One such factor he discovered was sufficient sleep. Published in his seminal papers and book Genetic Studies of Genius, Terman 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., a later) school start time: one that was in harmony with the innate biological rhythms of these young, still-maturing brains."

So why do we sleep? One big reason is that it literally stores your memories from the day - it moves them from short term to long term storage, and if you don't get good sleep, you just lose the memories! I shudder to think of how many classes I crammed for during college on no sleep and then promptly forgot it all :(. The phrase "let me sleep on it" exists in every culture because it works - our brains will be better on a problem the following day, because the information has been moved to long term storage, and intermingled with our neural net of everything else in our brains.

"Of the many advantages conferred by sleep on the brain, that of memory is especially impressive, and particularly well understood. Sleep has proven itself time and again as a memory aid: both before learning, to prepare your brain for initially making new memories, and after learning, to cement those memories and prevent forgetting."

"Before having slept, participants were fetching memories from the short-term storage site of the hippocampus—that temporary warehouse, which is a vulnerable place to live for any long duration of time if you are a new memory. But things looked very different by the next morning. The memories had moved. After the full night of sleep, participants were now retrieving that same information from the neocortex, which sits at the top of the brain—a region that serves as the long-term storage site for fact-based memories, where they can now live safely, perhaps in perpetuity."

When it comes to information 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 these raw ingredients with each other, with all past experiences, and, in doing so, building an ever more accurate model of how the world works, including innovative insights and problem-solving abilities)."

One fascinating insight was the studies that showed that the last 2 hours of sleep (from hour 6 to 8) were some of the most key hours for deep NREM sleep, which does your memory storage. When you short those by only getting 6 hours, it matters a lot!

"The increases in speed and accuracy, underpinned by efficient automaticity, were directly related to the amount of stage 2 NREM, especially in the last two hours of an eight-hour night of sleep".

The bits about physical performance for athletes was solidly backed and fascinating. I'd heard that "Federer gets 9-10 hours" and the such for similar top performers, but this backed it up - you really do perform 30-50% better with more sleep, AND recover 30-50% better with more sleep the next night.

"Obtain anything less than eight hours of sleep a night, and especially less than six hours a night, and the following happens: time to physical exhaustion drops by 10 to 30 percent, and aerobic output is significantly reduced. Similar impairments are observed in limb extension force and vertical jump height, together with decreases in peak and sustained muscle strength."

The book had several convincing chapters about the improved health risks of sleeping more. It reduces chances of cancer and probably about everything else, since sleep is what helps your body repair itself. These bits were scary to read, and intended to be so. His "convincer", that he opened his TED Talk with, is that men who are sleep deprived have 30% reduced sperm count, lower testosterone, and smaller testicles.

"Poor sleep quality therefore increases the risk of cancer development and, if cancer is established, provides a virulent fertilizer for its rapid and more rampant growth. Not getting sufficient sleep when fighting a battle against cancer can be likened to pouring gasoline on an already aggressive fire."

Another scary stat is that Drowsy Driving is worse than Drunk Driving. How much education and laws do we have about drunk driving, and yet being drowsy is the cause of more vehicle accidents than being drunk! Time to shift our education and perhaps our laws.

While the book was great at the science of what we know about sleep, it didn't go enough into what is known about how to improve sleep. But it did have good high level tips:

Key Tips to Improve Sleep
1. Reduce electric and LED light. Simply put, we weren't designed to stay up until midnight, and so reducing light, especially harmful blue light, will let us get to sleep easier. This means creating mood lighting hours before bedtime to start to suppress melatonin. Wear blue light glasses, especially if looking at any screens after dinner, and avoid screens 2 hours before bedtime. "A subtly lit living room, where most people reside in the hours before bed, will hum at around 200 lux. Despite being just 1 to 2 percent of the strength of daylight, this ambient level of incandescent home lighting can have 50 percent of the melatonin-suppressing influence within the brain.
2. Keep a cool bedroom, cooler than you think: A bedroom temperature of around 65 degrees Fahrenheit (18.3°C) is ideal for the sleep of most people, assuming standard bedding and clothing."
3. Establish a regular bedtime and wake-up time, even on weekends: "if you can only adhere to one of these each and every day, make it: going to bed and waking up at the same time of day no matter what. It is perhaps the single most effective way of helping improve your sleep, even though it involves the use of an alarm clock."
4. Don't have caffeine after noon as it will be in your system 9 hours later.
5. Avoid or limit alcohol, which has a long half life: "alcohol fragments sleep, littering the night with brief awakenings. Alcohol-infused sleep is therefore not continuous and, as a result, not restorative."
6. Don't eat within 4 hours of bedtime.
7. Don't exercise within 2-3 hours of bedtime.
8. Have a completely black sleeping environment: Maintaining complete darkness throughout the night is equally critical, the easiest fix for which comes from blackout curtains."
9. Have a hot bath or shower before bed: "Hot baths prior to bed can also induce 10 to 15 percent more deep NREM sleep in healthy adults".

I did want more tips on beating jet lag, which the book didn't really go into, other than to say it will take 1 day to adjust 1 hour, so it takes a week to adjust to a move from the US to EU (which I knew).

I bought an Oura ring after reading this book, which gives great data and graphs about my sleep, but I am still struggling to get high Oura scores. So I'm still looking for what works for me. But now I'm committed to striving for 8 hours a night instead of 7, which has already made a big difference!
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Reading Progress

October 25, 2018 – Shelved
October 25, 2018 – Shelved as: to-read
April 19, 2019 – Shelved as: nonfiction
April 19, 2019 – Shelved as: self-improvement
October 8, 2019 – Started Reading
October 16, 2019 –
14.0%
October 21, 2019 –
22.0%
November 13, 2019 – Finished Reading
November 27, 2019 – Shelved as: science
November 27, 2019 – Shelved as: health

Comments Showing 1-4 of 4 (4 new)

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message 1: by Steve (new)

Steve Sarner Great review -thank you . Now get some sleep ;)


Petra-X Fantastic review. You saw things in the book that I missed. Thank you :-)


message 3: by Grumpus (new)

Grumpus This has been on my to-read list for a while, but based on your comments, I'm moving it up. Now that my girls are at college, I've been getting to bed earlier and moving up from 6 hours to 7.5 according to the Sleep Cycle app I use and recommend (free).


message 4: by Sharienne (new) - added it

Sharienne Absolutely, I have had to change my sleep schedule and I know it has saved my life. I had a horrifying health scare that has left me disabled and convinced that we are doing so much damage to ourselves and each other.
I recall watching an interview of Bill Clinton a few years after he left the White House and the increasing combative politics was clearly a problem. Clinton said, "It's lack of sleep." The host (possibly David Letterman) burst out laughing because he thought it was a joke. The former president laid out his argument with data and examples yet the host and audience couldn't believe he was serious. They continued to laugh and finally Clinton just dropped it, unfortunately. He brought up the commuting times that increased significantly in the 90s and 2000s. (I lived out there then and no joke on commute times) as well as increased number of hours Congress was expected to be in their districts and in the Capitol building for votes. It was disappointing that Clinton dropped the subject because it might have helped us to realize the damages we are accumulating. The worst being the hazing of doctors with such sleep deprivation is also killing us. From terrible care from ER docs who have become abusers to Malpractice we are suffering from their brains being chronically sleep-deprived.
An observation from a survivor: yawning is not contagious. I actually use it to gage how much sleep my kids need
One simple yawn and I know who needs to be in bed. My husband (poor guy) is the worst offender. But, I also catch myself, too. I realize that I need to check my sleep therapy if I am yawning with the rest of them. So, no, you don't have to yawn when someone else does. If you do, go to bed. Nobody will want tired you back once they meet you as a rested person.


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