Why We Sleep: Unlocking the Power of Sleep and Dreams - Book Review

Long read

The book explains the immense value of sleep in our lives, offers advice on how to improve it and so much more.

Why We Sleep is a good book. Matthew Walker has attained mastery in the field of sleep due to his intense love and studying of the subject for so many years, and his depth and quality of knowledge is apparent.

One thing I learned was about adenosine. Adenosine is a chemical that builds up throughout the day that makes you sleepy. If you have enough sleep, your adenosine levels plummet and go back to zero upon awaking. If you don’t, you carry this ‘sleep debt’ over into the next day, which is a not a good way to start your day for muultiple reasons. Also, you never actually recover lost sleep.

Another thing that will stay with me forever is the post-prandial dip in alertness, which is the dip in energy levels mid-afternoon. This is something all humans experience, which for someone who lives a healthy lifestyle consisting of a good diet and daily exercise, soothed some of my frustrations as to why I still experienced this. A way to combat this is a nap before the onset of the energy dip. Some of the largest companies in the world such as Nike, Google and NASA recognise and incorporate this, and so will I.

A good quality and quantity of sleep is also important for effective weight management. If you’re trying to lose weight, sleep well, and you lose more fat and keep more lean muscle. Sleep poorly, you lose less fat and lose more muscle.
However, as I progressed through the book, I found it harder to stay focused, as it was mainly Part 1 and 2 that I was interested in.

Overall, the core message of the book is that sleep is SO important, in more ways than you can possibly comprehend.

新品なのにカバーが曲がっている。

Highly recommend.

"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."

― from “Why We Sleep: Unlocking the Power of Sleep and Dreams”

Matthew Walker's "Why We Sleep" is one of the two most important books I have read in my life1. Having done a little stock trading along with having survived several tech industry "death marches," things which are quite antithetical to good sleep, I had little idea just how destructive to your health lack of sleep is. A few years back, however, I began to hear that lack of sleep was correlated with diseases such as Alzheimer's, but this did not strike me as convincing since correlation is not causation. Indeed, a little later, I heard about this book at work but was somewhat ambivalent. It's just going to tell me that doctors think sleep is essential but are vague as to why were my thoughts.

Luckily I noticed an episode of Sam Harris's podcast "Making Sense" in which he interviewed Walker. Since Sam Harris is a figure whose judgment I highly respect, and I know he is very discerning about whom he invites on as guests, I decided there was probably more of value to say about sleep than I initially thought.

Correlation and Causation

Walker's book makes a compelling case that sleep is the bedrock of good health. He convincingly demonstrates that lack of good sleep can lead to downward spirals in health with the development of health conditions that make it hard to sleep, leading to more serious health conditions due to lack of sleep, making it even harder to sleep… and so on into a vicious cycle. Walker is careful to lay out in detail when the causal mechanisms are well understood, as in the case of Alzheimer's and cancer, and when lack of sleep is currently a suspect, although the exact causal mechanism has yet to be established. By the end of the book, I realized, however, that sleep is so foundational that even a mere correlation to some bad health condition is enough to make lack of good sleep a prime suspect worth considering as a cause.

Organization and Style

According to Walker, "Why We Sleep" is organized so that later chapters can be read without a strict need to read earlier ones first. Thus, if you use sleeping pills and want to know why you should not, he says it is okay to and, indeed, encourages you to jump to that section right away. That being said, I found the writing style so engaging (with a few minor instances of excessive detail) and the content so important that I read it straight through. Having read it this way, my sense was that the book frontloads its most important content: It explains in detail, with specifics such as the chemicals involved, why you feel more tired at certain parts of the day than others. To give you the motivation to get good sleep, the deleterious effects of lack of sleep also come near the beginning of the book.

The Enormous and Far-Ranging Effects of Poor Sleep

The effects of lack of sleep go beyond just affecting your physical health, however, and Walker shows just how destructive lack of sleep will be on your ability to learn new things. One of the most remarkable findings is that you need to get good sleep after learning new information. You cannot even get a single night of suboptimal sleep the first night, or some information will be lost permanently.

Conversely, if you get that first night of good sleep after learning something new, sleep on subsequent nights will continue to solidify what you have learned: all while you sleep! This is just one case where Walker details how, unfortunately, missed sleep cannot be well compensated for by more sleep later: Permanent losses are involved.

Dreams

Some of the most fascinating information in the book is on the role of dreams. Here we learn of their therapeutic qualities, including some of the underlying biochemistry involved. Discoveries here have led to a better understanding of PTSD, including better treatment methods. Walker also describes how dreams foster creativity by establishing connections between distantly related pieces of information stored in the brain. Here Walker includes a particularly fascinating anecdote of how Edison enhanced his creativity by waking himself from naps and immediately recording his thoughts.

Empathy For Different Circadian Rhythms

Throughout the book, Walker emphasizes how what we have learned about sleep has implications for how we should view people who may not have what seem like "normal" sleep patterns more empathetically. In particular, he emphasizes that teenagers want to get up and go to bed later, not due to laziness but because they run on a different circadian rhythm. It is something that is biologically hardwired into them. A consequence is that forcing school start times incompatible with this has devastating effects on how well they learn compared to well they could. Similar facts are true of people who are naturally "night owls" and run on different circadian rhythms than the rest of us.

Minor Flaws

Walker's book has only a few minor flaws:

1. Although he provides an excellent explanation of why most sleeping pills should be avoided, he does not mention whether this includes melatonin.

2. His discussion of the nationwide dollar impacts of poor sleep could be better presented. The unfortunate truth is that given the numbers we have heard spent on wars and, especially, financial bailouts and stimulus, rattling off numbers that are “merely” in the hundreds of millions or even low billions hits us in a place we are now numb.

3. Although Walker's discussion of creativity in the dream state and the state when just waking from dreams is a fascinating part of the book, I would have liked to see some discussion of how objectively accurate intuitions are during these moments. Anecdotally, I used to joke that my best ideas came to me during this time or not at all. Sometimes, however, the thoughts just turned out to be overconfident upon more profound reflection. Is that true for just me, or is it true for people, generally speaking?

Conclusion

Overall, Walker's "Why We Sleep" is a must-read for anyone who sleeps: in other words, everyone. This book will not only absolve you of any guilt associated with prioritizing sleep, but it will also arm you with the knowledge to make the best choices for your physical and mental health. Walker guides you through the critical benefits of sleep, from its integral role in memory and creativity to its power to process and put to rest the day's experiences: especially the more troubling ones.

While the damaging effects of lack of sleep seem exponential, Walker argues that some of the most significant benefits come in the final two hours. Thus getting eight full hours of sleep is crucial. After reading this book, you will not want to miss a full night's sleep again.

To help you achieve a full night's sleep regularly, Walker provides 12 concrete steps in an appendix. Some of these suggestions are initially counterintuitive. For example, Walker maintains that a cooler room temperature of around 65F is best for optimal sleep. Already, I've been putting this and his other advice to the test, and the results seem promising.

Great book. Read it.

Understanding sleep and how we should interact with our bodies is extremely important. Besides talking about sleep and supporting research, there are suggestions on how to improve sleep. I follow some of those guidelines and have seen improvement in my sleep. The one I take rather seriously is minimizing blue light exposure before bedtime. Absolutely makes a difference.

Life changing book. Never knew how important sleep is. It is written in a great and playful way

Writes well, but so repetitious, and disappointing, as little in the way of actionable, practical remedies.

Just finished half of the book and have learned many important things about sleep which we thought we knew a lot but actually not quite.

If u are concerned for your health, this is must read.

This book has a lot of important information and everyone should take the time to read it! Truthfully, I was worried this book would be boring and I wouldn’t want to finish it but it grabbed my attention immediately with the intriguing information it was giving. It’s a must read!!

I had no clue how important sleep was and I certainly wasn't giving it the credit it deserves in my health. This book should be required reading for parents, kids in school etc. Do yourself a favor and buy it!

This book was boring. Too many studies and research. It’s good but I just want something straightforward. overall the summary of the whole book was sleep is important and you should sleep more and avoid staying up late. That’s it. Literally just go online and search up how to sleep better. This book is more for scientists. I just want to know how to sleep better. You are better off searching the answer online.

Great book. Great price

Everyone should read.

I loved the stories and the studies from this book and I enjoy all of Walker’s content on YouTube etc. The scientific studies really nail down the importance of sleep. But being honest I understand the value of it before and read this to try to improve my sleep. The tips are basically just 4ish pages. I understand that he only wants to discuss the firmly proven tips rather than ones with preliminary evidence, but I expected more.
I’d recommend the book Sleep Smarter for pretty much every sleep tip with some solid studies to back them up

Ich habe viel mit Biologie am Hut, darum war dieses Buch, was nun mal ziemlich viel Wissenschaft enthält, leicht zu lesen. Solange man sich nicht explizit mit allen Vorteilen des Schlafens auseinandergesetzt hat, lernt man viel Neues über die Wichtigkeit von Schlaf, was der Schlafrhythmus bedeutet, wie die innere Uhr funktioniert, wie sich Schlafmangel aufstaut, und auch die Art, wie das Erlernen von Dingen funktioniert. All diese Punkte werden exemplarisch begleitet von verschiedenen Studien, die nicht einfach aufs Appendix verwiesen werden, sondern im Buch direkt erklärt werden.

Wer sich für Biologie interessiert und den Schlaf aus Sicht der Forschung, oder auch generell kennenlernen möchte, sollte definitiv dieses Buch Why We Sleep lesen.

"I recently finished reading this book about the importance of sleep, and I found it incredibly informative. The author explains in detail why sleep is so essential for our bodies and the many harmful effects of not getting enough sleep. I bought this book a year ago on Amazon, and it was definitely worth the purchase. If you're looking to improve your sleep habits and learn more about the benefits of a good night's rest, I highly recommend giving this book a read."

Scientifically explain about sleep starting from before birth up to death, even it covers sleep's evolution in animals. Author talks about important of sleep in memory and physical fitness. Surprise to know that sleep influence in sportsman and musician's performance also. Many of us think that nap is not good, but as per research nap helps to improve memory. Thanks to Matthew Walker to write in easy language.

Easy read

We all know lack of sleep will screw our body.
Though we repeat the habbit.
This book is like a science book for me.
once we read this, we get to know what really happens when we lack sleep or when we have coffee.
More the knowledge, more the awareness. Better will be our behaviour to break the habbit.
I enjoyed reading it. More of a theory book. But important to all.
Thanks to the Author and Publisher.

I can't say how many times I've recommended this book. I prefer the audiobook because the narrators voice puts me to sleep (but not in a boring monotone type of way, in a good way). There is so much knowledge in this book and it has definitely made me make sleep a priority!

Very difficult to read and understand. Disapointed language very difficult to understand. A lot about experiments tiny descriptions