Review:
Why We Sleep, by Matthew Walker
| Publisher: |
Scribner |
| Copyright: |
October 2017 |
| ISBN: |
1-5011-4433-2 |
| Format: |
Kindle |
| Pages: |
341 |
The world is full of theories, and corresponding books, about things that
will make you healthier or prevent disease. Nearly all of them are scams,
either intentional or created through the placebo effect and the human
tendency to see patterns that don't exist. The rare ones that aren't have
a certain pattern: they're grounded in our best understanding of biology,
align with what our body wants to do anyway, have been thoroughly studied
using proper testing methodology, and don't make money for powerful
corporations.
I'm fairly sure this is one of those rare ones that isn't a scam. And, if
so, it's rather important and worth your attention.
Matthew Walker is a professor of neuroscience and biology at the
University of California at Berkeley, where he's the founder of the Center
for Human Sleep Science. He's not a doctor; he started medical training,
but (as he says in the book) found himself more attracted to questions
than answers. He's a professional academic researcher who has been
studying sleep for decades. This book is a combination of summary of the
current state of knowledge of academic sleep research and a plea: get more
sleep, because we're literally killing ourselves with the lack of it.
Walker opens the book with a discussion of the mechanisms of sleep: how we
biologically fall asleep and why, how this has changed over time, and how
it changes with age. Along with that, he defines sleep: the REM and NREM
sleep cycle that you may have already heard of, how it manifests itself in
most people, and where dreams fit in. The second part then discusses what
happens when you sleep, with a focus on what goes wrong when you don't.
(Spoiler: A lot. Study after study, all cited and footnoted, has found
connections between sleep and just about every aspect of mental and
physical health.) The third part does the same for dreams, fitting them
into the picture along with a scientific discussion of just what's going
on during dreams. The fourth and final part tackles the problem: why
don't we get enough sleep, and what can we do about it?
I will warn in advance that this book will make you paranoid about your
sleeping patterns. Walker has the missionary zeal of an academic who has
sunk his teeth into something really important that society needs to take
into account and will try to drown you in data, analysis, analogies, and
sheer earnestness until you will believe him. He wants you to get at
least seven, and preferably eight, hours of sleep a night. Every night,
with as little variation as you can manage. Everyone, even if you think
you're someone who doesn't need as much sleep (you're probably not).
There's a ton of science here, a great popularization of a whole field of
research, but this is also a book that's trying to get you to do
something.
Normally, that sort of book raises my shields. I'm not much of a believer
in any book of the general genre of "most people are doing this basic part
of life wrong, and should do it my way instead." But the hallmarks of
good science are here: very widespread medical consensus, no corporate
interest or obvious path to profit, and lots of studies (footnoted here,
with some discussions of methodology although not the statistical
details, which will require looking up the underlying studies and
careful caveats where studies indicate correlation but may not find
causes). And Walker makes the very telling point early in the book that
nearly every form of life on the planet sleeps in one way or another
(defined as a daily recurring period of time during which it doesn't
respond to outside stimulus), which is a strong indicator of universal
necessity. Given the vulnerability and loss of useful hours that come
with sleep, one would expect some species to find an evolutionary path
away from it if it were dispensable. But except for extremely short-lived
species, we've never found a living creature that didn't sleep.
Walker's argument for duration is also backed up by repeated studies on
human capability before and after various quantities of sleep, and on
studies of the sleep phases in various parts of the night. Study after
study used six hours as the cutoff point and showed substantial
deterioration in physical and mental capabilities even after only one
night of short sleeping. (Reducing sleep to four hours is nearly
catastrophic.) And, more worrisomely, that degradation is still
measurable after "catching up" on sleep on subsequent nights.
Sleeping in on weekends doesn't appear to fully compensate for the damage
done by short-sleeping during the week.
When Walker gets into the biological reasons for sleep, one starts to
understand why it's so important. I think the part I found the most
fascinating was the detailed analysis of what the brain is doing while you
sleep. It's not inactive at all, even outside of REM sleep. Walker and
other sleep researchers have done intriguing experiments showing how
different parts of the sleep cycle transfer memories from short to long
term storage, transfer physical skills into subconscious parts of the
brain, discard short term memories that the conscious brain has tagged as
being unwanted, and free up space for new knowledge acquisition. REM
sleep appears to attempt to connect otherwise unrelated memories and bits
of knowledge, inverting how association normally works in the brain, thus
providing some concrete explanation for sleep's role in creativity. And
(this research is fairly new), deep NREM sleep causes temporary physical
changes in the brain that appear to be involved in flushing metabolic
waste products away, including the plaque involved in Alzheimer's.
The last part of the book is probably the most concretely useful: what can
one practically do to get more sleep? There is quite a lot that's proven
effective, but Walker starts with something else: sleeping pills.
Here, you can almost see the lines drawn by a lawyer around what Walker
should say. He stresses that he's not a medical doctor while laying out
study after study that all point in the same direction: sleeping pills are
a highly dangerous medical fraud that will shorten your lifespan for
negligible benefit in helping you fall asleep, while limiting your brain's
ability to enter true sleep. They're sedation, sedation is not sleep, and
the four
billion dollar sleeping pill market is literally making
everything worse.
The good news is there is an effective treatment for insomnia that works
for many people; the better news is that it's completely free (although
Walker does suggest some degree of medical supervision for serious
insomnia so that some parts of it can be tailored to you). He walks
through CBT-I (cognitive behavior therapy for insomnia), which is now the
medically recommended primary treatment for insomnia, and takes apart the
pieces to show how they line up with the results of sleep research
studies. Alongside that are recommendations for improving sleep for
people who don't have clinical insomnia but who aren't regularly getting
the recommended amount of sleep. There are a lot of interesting bits here
(and he of course talks about blue LED light and its relationship to
melatonin cycles), but I think the most interesting for me was that you
have to lower your core body temperature by a couple of degrees
(Fahrenheit) to enter sleep. The temperature of your sleeping environment
is therefore doubly important: temperature changes are one of the signals
your body uses to regulate circadian rhythms (cold being a signal of
night), and a colder sleeping area helps you lower your core body
temperature so that you can fall asleep. (The average person does best
with a sleeping room temperature of 65F, 18C.)
There's even more in here: I haven't touched on Walker's attack on the US
tendency to push high school start times earlier and earlier in the day
(particularly devastating for teenagers, whose circadian rhythms move two
hours
later in the day than adults before slowly returning to an
adult cycle). Or the serious problems of waking to an alarm clock, and
the important benefits of the sleep that comes at the end of a full
night's cycle. Or the benefits of dreams in dealing with trauma and some
theories for how PTSD may interfere with that process. Or the effect of
sleep on the immune system.
Walker's writing style throughout
Why We Sleep is engaging and
clear, although sometimes too earnest. He really wants the reader to
believe him and to get more sleep, and sometimes that leaks around the
edges. One can also see the effort he's putting into not reading too much
into research studies, but if there's a flaw in the science here, it's
that I think Walker takes a few tentative conclusions a bit too far. (I'm
sure these studies have the standard research problem of being frequently
done on readily-available grad students rather than representative samples
of the population, although the universality of sleep works in science's
favor here.) Some of the recitations of research studies can get rather
dry, and I once again discovered how boring I find most discussion of
dreams, but for a first book written by an academic, this is quite
readable.
This is one of those books that I want everyone to read mostly so that
they can get the information in it, not as much for the enjoyment of
reading the book itself. I've been paying closer attention to my own
sleep patterns for the last few years, and my personal experience lines up
neatly with the book in both techniques to get better sleep and the
benefits of that sleep. I'd already reached the point where I was
cringing when people talk about regularly going on four or five hours of
sleep; this is an entire book full of researched reasons to not do that.
(Walker points out that both Reagan and Thatcher, who bragged about not
requiring much sleep, developed Alzheimer's, and calls out Trump for
making the same brag.) The whole book may not be of interest to everyone,
but I think everyone should at least understand why the World Heath
Organization recommends eight hours a night and labels shift work a
probable carcinogen. And, as Walker points out, we should be teaching
some of this stuff in school health classes alongside nutrition and sex
education.
Alas, Walker can't provide much advice on what I think is the largest
robber of sleep: the constant time pressure of modern life, in which an
uninterrupted nine hour sleep opportunity feels like an unaffordable
luxury.
Rating: 9 out of 10
A first maintenance release of 
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My monthly report covers a large part of what I have been doing in the free software world. I write it for 
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Today I spent some time in the morning seeing how one would install the JDK
on Linux distributions. This is to create a little comparative tutorial to
teach introductory Java.
Installing the JDK is, thanks to the OpenJDK developers in Debian and Ubuntu
(Matthias Klose and helpers), a very easy task. You simply type something
like: