REVIEW: Why We Sleep

Introduction

Why We Sleep was written by Matthew Walker, an English scientist and professor of neuroscience and psychology. There are several YouTube videos by different channels featuring professor Walker. I think I first saw him in this video by Penguin Books UK. He was also featured on Joe Rogan’s podcast, which is a great summary of the book’s main ideas. Professor Walker seemed very genuine and eager to educate people about sleep, and overall very pleasant to listen to. Shortly after that I came across his book in my local book store, so I decided to pick it up. I’m glad I did!

I Feel Sleepy

Considering that sleep is such an integral part of our lives, it’s kind of shocking how little effort we put into education ourselves on that topic. I’m sure there are many other books about sleep, but they did not come across my radar. I get the impression that overall people have a very loose attitude towards sleep, and sleeping less hours is often seen as ‘hardworking’ or otherwise worth of praise. We all grew up thinking it’s normal and fine to deprive ourselves of sleep and somehow it became a social norm to pull an all-nighter for exams and deadlines. But, is it really normal to sacrifice sleep for ”more important” things?

When you think about it, we humans are the only species on Earth who intentionally deprive ourselves of sleep! We may tell ourselves it’s for a higher good, like studying for an exam, but is this really the best strategy? While we are in this process, we are not aware of how much our capacity to learn has decreased, or how much more time we need to remember something compared to when we get a full night of sleep. Someone might say that life happens while you are awake, and sleep is something worth sacrificing. But isn’t it a bit arrogant to think we can function just as well without enough sleep and have no consequence what so ever on our health and general quality of life?

Sleep is something that has been deeply embedded in our biology for millions of years. It’s not something we can just decide to skip or control with our will power alone, just as we can’t decide to live without food or water. You know when you are hungry or when you’ve eaten more than you need. It’s similar with sleep, if you can’t possibly wake up without an alarm clock, or if you can fall asleep within an hour of waking up, you probably did not get enough sleep.

Book Structure

The book is divided into 4 parts:

1. This Thing Called Sleep
2. Why Should You Sleep
3. How and Why We Dream
4. From Sleeping Pills to Society Transformed

Each part has several chapters, and each chapter could be read separately, so if you see a topic you are particularly interested in, you can skip to it directly without being lost.

So Why Do We Sleep?

Basically, all living beings with some kind of central nervous system need sleep to survive, and humans are no different. As professor Walker states, when looking at it from an evolutionary perspective, sleeping seems kind of silly – you are not searching for food or a mate, you can’t socialize, you can’t take care of your children, and you are in a very vulnerable state to outside conditions. Yet, sleeping still prevails as a mandatory part of our biology, which just tells you that it must be very important!

The question of why we sleep might suggest there is only one answer, while really there is hardly any organ in our body, or process in our brain, which does not get some kind of regeneration or optimization for future work while we sleep. To name a few important benefits of regular, good quality sleep: it boosts your immune system so you’ll get sick less often, it helps you maintain a healthy weight, reduces the risks of diabetes and cardiovascular diseases, improves your memory, your learning ability, and reduces stress. Sleep is indeed a superpower!

Our Sleeping Rhythm

In the first section of the book, professor Walker explains the circadian rhythm. The message here is that each of us have our own biological rhythm for sleeping and being awake, which does not necessarily have to align with the usual school and working hours. This is something easy to accept as true, as you have surely seen evidence of it. An early bird I am not – I like the time between 9 PM and midnight the most, in that time I feel I can be productive and have fun with my hobbies. On the flip-side, there are people who can’t possibly function after 9 PM, but naturally wake up very early in the morning.

The thing is, our industrialized way of living is biased towards ‘early birds’, and sleeping late is often seen as a sign of laziness. What people sometimes fail to see is that the person who wakes up later, also stays awake later in the night, and might be very productive in his work during this time! It’s hard (if not impossible) to create a working schedule that will suit everyone, but it would be good to start re-evaluating certain things based on what we now know about sleep. Starting school at 7 AM means that some kids who live further away need to get up at 6 AM or even earlier…what is wrong with you people?!

Can I Get Away with Less Sleep?

When we sleep, we go through cycles of two phases of sleep: REM (rapid eye movement) and non-REM. Both are essential and come in different amounts depending on the time of the night. In the first part of the night we experience more non-REM sleep, while REM sleep is more dominant in the second part of the night. This means that you can’t just ‘cut’ your regular night of sleep on one end or the other without sacrificing some essential regeneration of your body and mind. The thing is, people who are chronically under-slept are often not aware of it and they accept this version of themselves as the new baseline. Even if you convince yourself otherwise, it’s extremely unlikely that you can function properly, without any compromises on your abilities, unless you get regular quality sleep of 7 to 9 hours every night.

One thing to note is that the quality of sleep is just as important as the quantity. Consuming caffeine any time after early afternoon will impact your quality of sleep. Even if you are the type who can drink an espresso and go straight to bed, the brain still has to deal with that caffeine in your system, which means that your quality of sleep will be compromised!

Fun fact: the doctor who helped start the first surgical residency training program in the US (a program associated with long, sleepless shifts), and who was known for being able to perform with very little sleep, was shown to be a cocaine and morphine addict!

Not Even a Little Bit?

What if you’re working night shifts, studying for an exam overnight, or going out with friends? There are, of course, a lot of instances where we will sacrifice some sleep for other activities in life. This is up to each person to decide on, the point is that you should be aware of the drawbacks of less sleep, and use your time in a smart way to achieve your goals. Staying healthy and in optimum mental conditions is probably a good plan for everyone. If improving your sleeping habits can help that, then it’s something worth thinking about.

Conclusion & Verdict

For a popular science book about sleep, Why We Sleep checks all the boxes for me. I felt it was easy to read and the content was presented in a nice, structured way. There were scientific explanations for sleep related phenomena backed up by numbers and diagrams, which I found interesting and informative. I really liked the explanation of the circadian rhythm and how it’s connected to different hormones in the brain.

In some instances, when percentages were used to make certain claims, I wondered what the exact sample size or the profile of people who attended the study was. I just got the feeling throughout the book that some presented data was exaggerated, maybe on purpose. This, however, did not bother me too much as it all serves the main point: to get people aware about the importance of sleep.

Overall, I think this is a book everyone should read. Sleeping is an essential part of our lives, and this book can help you learn something about it. At the end of the book you also get 12 tips for good sleep, which you can check out here. Sleep well!

Rating: 5/5