Why We Sleep: Book Review

This page may contain affiliate links, meaning we receive commissions for purchases made through those links, at no cost to you. Please read our disclosure for more info.

Why We sleep book review

We spend nearly a third of our life asleep. Why? The book “Why We Sleep” by Matthew Walker answers this question and many more surrounding the topic of sleep.

Originally, I decided to read this book due to a conversation I had with a friend of mine who works in management consulting. During one of their trainings they had a workshop with a life coach who gave them insights on nutrition, productivity and sleep. The main concepts with regards to sleep related mainly around having a consistent time of going to bed and waking up.

I am a heavy sleeper. Even as a baby I would sleep more than other children. Naturally after this conversation, I sought out more information on sleep and stumbled across Matthew Walker’s book.

Here is what I took away from the book and what advice I actually gleaned from it.

The Author: Matthew Walker

Matthew Walker is an English who received a PhD in neurophysiology from the University of Newcastle. He then went on to teach at Harvard University and the University of California, Berkley, where he still is today.

At Berkeley, Walker is the founder and director of the Center for Human Sleep Science which does all kinds of research surrounding sleep. One of his collaborations outside of Berkeley is with the company Verily, a sub-organization of Google. Together, they research the link between Sleep and Health

To date, “Why We Sleep” is the only book published by Walker. In total, it took him four years to write the book and it immediately become an international best-seller.

The Structure

The book is structured into four main parts, each with its specific focus on a different aspect of sleep:

The first part explains what sleep is and how it is structured. Walker takes the readers through the individual stages of sleep (e.g. REM, light sleep, deep sleep) and how our own sleep patterns differ from those of other animals.

The second chapter answers the question “Why should we sleep”. In essence, he shows what impact sleep deprivation can have on the human body and mind, both in the short- and long-term. He is able to link it to reduced learning capabilities, memory loss and various diseases such as cancer and Alzheimer’s disease.

The third chapter illustrates why we dream. He dives a lot into the topic of that dreams are here for us to digest our experiences in life.

The final part of the book creates a link between modern life and sleep. The topics covered are quite diverse, such as the impact of sleeping pills on modern day society and an individual, the relation between sleep deprivation and ADHD, and the impact of technology (i.e. phones, tablets and computers) on sleep quality.

One of the most important parts of the book is actually the annex where Walker gives 12 tips on how to improve your sleep.

Key Learnings

Before I dig further into my key learning I need to state two things. First, I skimmed through chapters 1 and 3, but spent a lot of time on 2 and 4. Why? Because these two seemed to have much more actionable advice and real-life impact than the other two chapters.

This would also be my only criticism of the book. The key messages could have been made with 60% of the words actually used. Walker loves to go into the theoretical aspect of sleep as well as the results of many, many studies. I do not blame him, after all he is a researcher.

But the block is chock-block full with interesting learning and actionable advice overall. Here are my top three key learnings:

1. Sleep Is Key To My Happiness

This sounds simple, but I think it is something we often forget. I even remember myself using the over-used phrase “I can sleep when I am dead” (yes, I was young and naïve). 

Currently, I work in a job where I consistently get less than six hours of sleep. This simply is not enough and when I look at the links Walker can make between sleep and various diseases, I shiver.

Sleep is important for our recovery (both body and mind), it is important for our short-term and long-term health, and we cannot survive it. There is no excuse for not taking it seriously.

I made a promise to myself that I will start investing more in making my sleep both longer and better. We spend a lot of effort getting better at sport and our work. Why not invest the same mentality in something that takes up a third of our life?

This is my first and most simple learning: sleep is important to my happiness!

2. Modern Day Society + Good Sleep = Difficult

There are multiple aspects which make this equation true for me. First, is the whole topic surrounding sleeping pills. Walker clearly shows that while sleeping pills help us fall asleep, it is less of a sleep state and more of a sedated state. 

In sedated state, we shut off a part of our brain which is essential for us to obtain good and regenerative sleep. Given the unbelievably high number of sleeping pills used around the world (incl. Switzerland, XXXX per XXX) this is a real cause for concern. If you cannot sleep, good sleep hygiene (i.e. behaviors) is the solution, not a sleeping pill.

In addition, modern day technology is not conducive at all to sleep. Walker explains that the light given from our modern day screens (phones, tablets, etc.) prevents our brain from becoming tired. So even while we might feel tired physically, the moment we hit the bed, our brain is still awake. It will then take the brain some time to calm down and let us actually sleep.

He further delves into the topic of early school start times and how they influence performance of students, as well as how we treat ADHD with medicine, rather than focusing on getting the affected people a better sleep routine.

It is just unbelievably fascinating what topics of our normal everyday life touch our sleep and how they affect them. 

3. You Can Improve Your Sleep

Again, this is a very simple message that I took from the book. No matter how old or young, what medical condition you have or not, everyone has tools available to improve their sleep. It does not mean that you will achieve it, but everyone has simple tools available to try.

All of the twelve actions Walker proposes in the Annex can be implemented by anyone. I will not divulge all of the steps, but the most important step and most effective step is too go to bed and wake up at the same time, no matter whether it is a weekday or a weekend. Our body is wired to get up at sunrise and go to sleep at sundown. This does not change from one day to the next. Therefore, our sleep should always start and end at similar times, even in non-natural light.

Conclusion: Main Actionable Items For Me

I absolutely loved the book. Why? Because it gave me a deeper appreciation for sleep in addition to some very simple actionable items. I have now recommended this book to many friends and family. 

From this book, I took five main actions for myself:

  1. Wake up at the same time every morning.
  2. Avoid screens before going to bed and right after getting up.
  3. No coffee after 4 pm.
  4. Lower the room temperature for sleep.

What effect these actions had on my sleep quality, you can read in my post on “How To Sleep Better: A Self Experiment“.

Overall my recommendation to anyone is: Get this book, read chapter 2 and chapter 4, implement any number of steps from the annex of the book. Thank me later. And Walker as well. 

Actionable Items


  • Buy the book “Why We Sleep” or research good sleep routines online.
  • Implement just one thing which will help you sleep better, for example:
    • Go to sleep at the same time every night
    • Get up at the same time every morning
    • Lower room temperature
  • Discuss sleep with your friends and family, especially the effect of sleeping pills on your brain and sleep quality.

How is your sleep? What are your routines and do you wake up refreshed? What things would you like to change about your sleep?

Let me know in the comments or send me an e-mail at info@chocolateandmoney.com. Any questions, concerns, feedback and constructive criticism is highly appreciated.

Leave a Reply

Your email address will not be published. Required fields are marked *