Book Review: Why We Sleep: The New Science of Sleep and Dreams by Matthew Walker

I have long felt that I needed more sleep than most, but reading, or rather listening to, Matthew Walker’s excellent book, I have become convinced that we are all sleeping less than we should. Despite spending almost a third of our life sleeping, we still don’t entirely understand its functions. This book helps to demystify some elements of sleep and educate us about the essential role it plays in our well-being.

The first section of Walker’s book dives into what sleep is. He highlights the significant benefits of sleep, such as consolidating memories and aiding in problem-solving abilities. He goes into some depth around chronotypes (whether we are morning or evening people), the science behind it, and the changes to our chronotypes at different stages of our lives. This has been especially helpful for me as a parent of a teenager who is just starting to require more sleep in the mornings. Walker goes into some detail about the need for additional sleep in the mornings for adolescents, not just to help them grow, but also to capitalise on the benefits of REM sleep to help them catalogue memories and solidify learnings. Sleep is also vital for our immune system, and when we don’t get enough sleep, we become more susceptible to infections. Equally important is sleep’s effect on our mental health with lack of sleep identified as a potential cause for depression, anxiety and stress.

Walker goes into detail about the different stages of sleep. He explains the difference between REM and NREM sleep and how these stages work together to promote our health. He talks about the different roles that NREM sleep and REM sleep perform to help us recover and develop our bodies and mind. When we don’t get enough of both stages of sleep, our overall health and wellbeing are compromised. With more and more wearables available to rack different phases of sleep (obvs much less accurately than the Sleep Lab at UC Berkley) it is interesting to monitor how much of different types of sleep you are getting and know a bit more about what affect that has on your body and mind.

One area that I found particularly interesting was the explanation of the consequences of sleep deprivation. This section is truly horrifying, although does have some areas of light relief including when Walker explains that the very macho men who claim that they only sleep a few hours a night, are likely suffering from a wide range of issues including reduced testosterone levels and likely smaller than normal testicles. One section that was also particularly frightening was the explanation that being away for 19 hours and then getting behind the wheel of a car will leave you in a similar state to being at at the legal limit for alcohol. He caveats this statement with an explanation that the affect of alcohol is to dull your reaction time, whilst the affect of a micro sleep is to turn off your reactions all together so can in many cases lead to even worse outcomes. Chronic sleep deprivation can lead to a host of health problems, such as obesity, heart disease and diabetes.

I was also interested to find out about the affects on your sleep of sleeping pills. It does not make for good reading!

This book is well written, and I have subsequently also listened to Matthew Walker on a number of podcasts and interviews and have been very impressed by his knowledge and deep focus on sleep research. I have already given copies of this book to two people and would recommend it to anyone who wants to get the most out of their lives.

I would give this book 5 stars.