Why We Sleep by Matthew Walker

why we sleep matthew walkerIf like me you’re a chronic insomniac, or if you’re the parent of a young child or a carer or a shift worker, you may initially be put off by the tone of Why We Sleep. The author’s premise is that we are, as a society and as individuals, joyfully squandering our sleep time with terrible consequences – which he outlines, at length.

Like most people, there may have been a brief period in my teens and twenties when I wilfully deprived myself of sleep through a combination of alcohol and late nights, but I have spent many more years desperately trying to sleep through the night and feeling like a ghost in my own life as I struggle through the day. Still, I gave the book a chance and there is some interesting stuff in here.

The health benefits of sleep for physical and mental health are so great that he suggests, not entirely frivolously, that the question should be not why do we sleep, but why do we wake up? We need NREM (non-rapid eye movement) sleep to file away everything we’ve learnt during the day, to process it and move it from short-term to long-term memory. This is why cramming the night before an exam won’t work, because it’s sleep that allows you to properly integrate and retain what you’ve learnt.

I found what he said about REM sleep (where we dream) most interesting. This is where we make odd connections, have creative thoughts, gain a fresh perspective. Anyone involved in any kind of artistic project will know that feeling. You hit what seems like an insoluble problem, you go to bed and wake up the next morning with a solution that is not just feasible but feels inevitable. This applies as much in daily life – we talk about ‘sleeping on’ a decision all the time.

He’s a big fan of siestas (as am I) and talks about the genesis of the term ‘power nap’ which came from research on the optimum time for airline pilots to rest. It was found that a short sleep at the beginning of a long period of sleep deprivation (eg during a long-haul flight) was the most effective. The FAA decided to institute this as policy but rejected the suggested terms ‘prophylactic napping’ or ‘planned napping’ (the second was considered too managerial, the first, well you can guess). The trouble with the term ‘power napping’ is that it is now colloquially used to suggest a macho alternative to sleep, rather than a short-term expedient when a full-night’s sleep isn’t possible.

The book covers the body clock and circadian rhythms and even sleep in other species. The author also shares exhaustive evidence on the dangers of sleep deprivation, both immediate – such as driving while tired – and long-term, through poor health outcomes.

My slight qualm about the book is that the author is so evangelical about his position. You are left thinking that all the world’s problems could be solved if only we all got a regular eight hours sleep. He cites lots of research backing up his case but a general reader has no context. It’s a bit like watching a courtroom drama and being totally convinced by the prosecution’s case but not getting to hear the defence.

If you do have problems sleeping you are likely to be so frightened by this book that it will keep you awake at night. When was this golden age when everybody got their eight hours? How can we make the comparison? Maybe in past centuries people spent more time in bed (what he calls sleep opportunity) but unless you were wealthy you probably shared a room with several family members (and possibly other fauna). How much quality sleep would you have got in a room where a baby was teething or siblings were fighting or mice were scuttling?

The bit I was really excited about getting to was the chapter on insomnia treatments but all the author offered (after much fanfare) was the old cognitive-behavioural chestnut, which among other things insists on no napping (despite his earlier waxing lyrical on the benefits) and, more seriously, no reading in bed.

There’s a lot in Why We Sleep and overall I found it an interesting and informative read, albeit one without a miracle cure at the end of it.

I received a copy of Why We Sleep from the publisher via Netgalley.
View Why We Sleep on Goodreads


  1. I’ve avoided this one, partly because of past troubles with insomnia. My sleep isn’t perfect but it’s far better than it was largely thanks to another book: Colin Espie’s Overcoming insomnia and Sleep Problems.


  2. Sounds like an interesting read! I’ll have to keep it in mind for my sleepless nights! Also, REM sleep is why I keep a notebook beside my bed, I wake up constantly with some ides or another that I just have to write down… although, sometimes I wake up the next morning and look at it and think, “what is THAT supposed to mean??”


      1. EXACTLY!! I still have a memo in my phone (I couldn’t find my notebook that night) that I never finished about a woman who’s husband has ‘disappeared’ and it’s somehow related to a towel she’s using (don’t ask because I didn’t finish the memo!) I refuse to delete it hoping that someday whatever inspired it will come back to me!! Lmao!

        Liked by 1 person

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