Why We Sleep

Matthew Walker's discussion on Peter Attia's podcast (The Drive, Episodes 47 - 49) is one of the most interesting things I've ever heard. At six hours long, I was sad when it ended and immediately wanted to listen to it again. If you've any interest in sleep, I highly recommend you check it out immediately.

I picked up this book after hearing that podcast, and the book just isn't on the same level as those interviews. It's an entirely serviceable piece of science communication, but that's about it.

The text is a high level synopsis of key pieces of research and related anecdotes. It's interesting enough, but it just isn't very engaging. Dr. Walker does go through practical recommendations on how to get better sleep, but the focus is really on explaining what sleep is and isn't.

If you don't know much about sleep, and are looking for an overview of the science, this is probably a really good place to start. But I would honestly recommend just listening to the aforementioned podcast and using the book to reference terminology later.

Like any 21st century pop science author, the premise of a long book about sleep couldn't be a down-to-earth argument of marginal health improvements. Instead, it doubles down multiple times on how this has to be, "undeniably", the most important yet neglected health knowledge ever - a common recipe for best sellers, promising immense rewards for memorizing a few key concepts.

Stripped down of the obvious marketing strategy, the over-the-top framing and all the speculative fluff mixed in with the actual research data, the book does a good work on hammering the need of caring for our sleep. And like any book of its kind, in the end the advice is as predictable and close to common knowledge as one would guess:

1) Go to bed and wake up at the same time every day; 2) Exercise at least 30 minutes, not too close to bed time; 3) Avoid caffeine and nicotine after noon; 4) Avoid alcohol before going to bed; 5) Avoid large portions before going to bed; 6) Avoid medicines that delay or disrupt sleep; 7) Don't take naps after 3PM; 8) Relax before bed; 9) Hot bath/shower before bed; 10) Dark & cool bedroom, no screen devices; 11) Get morning sunlight every day; 12) Don't lie in bed awake;

Most annoying of all, no concrete answers on "why we sleep". Walker presents some speculative argumentation regarding what fits an evolutionary and utilitarian viewpoint, but very little evidence is available anyway and, most worryingly, zero counter-evidence or opposing research viewpoints are discussed. In the end, the answer currently available is as obvious as the 12 advices above: because it's good for us.

There was quite some 'I didn't know that!' in the book. What NREM and REM sleep do. What the consequences of deprivation are - both minute seeming (6 instead of the 7 to 8). How the brain develops over time (frontal cortex last, babies, kids and adolescents have vastly different schedules because of the development).

And of the things I did know, I learned the the background. Alcohol is a very good REM sleep precentor (and hence best avoided.at all cost). You really really need to sleep in order to learn. There's also a lot of repair going on from the brain damage ordinary day to day use is doing.

I was actually shocked how little I knew. Because of this book I have drastically changed my sleeping habits.

The writer has gotten some flak on two things (a yet unsupported claim lack of sleep causes dementia and the mention of a study with a woefully inadequate sample size), but that didn't detract from the rest of the book which seems to have solid backing and/ or medical consensus.

If you don't want to read this book, at least read the twelve tips for healthy sleep the American NIH has issued.

It’s 1/3 of our lives. We get no formal education on sleep and this is a crash course. You'll view and prioritize sleep differently, improving the other 2/3 as well.

Cons: It's incredibly long winded and dry. For every interesting or relevant fact, there’s 8 pages of participant results in various sleep studies to back it up. Despite the author's best efforts to make it easy reading (historical anecdotes and examples in the media), it’s effective at inducing sleep. I’ve been chipping away at this for two months.

There’s a lot to learn here. The history of human and animal adaptation, brain activity during sleep, the benefits of 8hrs, the health risks of less than 8hrs, circadian rhythm change through life, dreams and memory, sleep disorders and drugs, effective nightly routines, and suggested changes to our culture are in here between a lot of tedious and scientific verbiage.

Until there’s a more succinct option, everyone should read this book.

I often have trouble writing reviews because my REM sleep way of thinking makes my writing too disorganized and I'm too lazy to go back and edit afterwards as I should. I enjoyed this book and think its message an important corrective to societies attitudes toward sleep, but have a need to criticize it because he does some things which annoy me more than they'd probably ignore you so keep that in mind as I ramble on.

It is perhaps forgivable that the subject matter to which a person chooses to devote his life seems to him to be the most important in the world and in American culture, hours spent asleep not being directly billable means they are treated as lesser. Also, one can't buy things while asleep so those selling stuff wish we'd do less of it. Add to this that sleep seems mysterious, a seeming waste of a third of our lives and the need for it by the more macho among us is regared as a weakness.This book goes all out in the opposite direction, making the hours we spend asleep seem more important than those awake--that is those during which we do those things whose real purpose is to tire us out so that we can return to sleep, perchance to dream. Countless studies are cited proving that sleep cheats diminish both the quantity and quality of their lives, making them less creative, intuitive, funtional and more prone to diseases (cancer, alzheimers, cardiovascular, erectile).
Some of these studies gave me pause. For example, I know nobody will get a grant to repeat the creativity experiments performed on those awakened from REM sleep on those who have just smoked a doob but I imagine the results would be comparable.

Dr. Walker misunderstands psychoanalysis, thinking dream analysis to be a pseudoscience rather than the product of our 19th century understanding of science. It is actually more akin to the art of reviewing a book than anything a 21st century scientist might do. His example of interpreting the dream of his student Kyle (I wonder if he used his real name) rather than disproving Freud, supports Freud's concept of transference (which predicts that a student will tell his teacher that his interpretaion is correct--brilliant, even). I don't want to derail this any further defending Freud (who was wrong about a great many things, usually not exactly the same ones he's criticized for). I will say that some of the experiments Dr. Walker recounts made me question whether he was observing causation or merely correlation (a distinction he himself points out early in the book.) For example, did those dreamers who "worked out past difficulties" do so by dreaming about them or were those who were capable of dreaming (and remembering those dreams) about the subjects of conflict merely those who were capable of getting over them?

Here are some question I wish he'd answered:
1) Where do you draw the line between interrupted sleep (bad) and polyphasic or segmented sleep (presumably good or at least acceptable)?
2) Why is it better to arrange for your melatonin level to be controlled via light and temperature than by taking a pill?
3) Are sleeping pills so bad that they shouldn't even be used for harm reduction? That is, wouldn't abnormal sleep still be better than no sleep?
4) If I fall asleep because of low blood sugar, is that a bad form of sleep? Why or why not?
5) If sleep pressure is a matter of circadian rhythms and melatonin, what is the chemical or physiological basis for REM sleep pressure?

The section on Lucid Dreaming was fascinating, but seemed to belong in a different book. He should write that one (but leave out the speculation about it being a next evolutionary step).