Why We Sleep – Book by Matthew Walker

By: Elena Hein

“Scientists have discovered a revolutionary treatment that makes you live longer. It enhances your memory and makes you more creative. It makes you look more attractive. It keeps you slim and lowers food cravings. It protects you from cancer and dementia. It wards off colds and the flu. It lowers your risk of heart attacks and stroke, not to mention diabetes. You’ll even feel happier, less depressed, and less anxious. Are you interested?”

If this caught your attention, Why we sleep might just be the perfect read for you. In his book, neuroscientist Dr Matthew Walker is trying to open our eyes to the science of sleep and the effect it has on our health and wellbeing. Though, while the above paragraph certainly would get everyone curious about what is to follow, Dr Walker rather decided to open up the first pages telling us about all the consequences awaiting us when we neglect our beauty sleep. 

Everyone will be aware of the slow and tiring hours that follow a night of short and poor-quality sleep. You certainly know that you will feel less energetic, less able to concentrate on simple tasks and maybe even more emotional, stressed and easily agitated. After having read only the first page of Dr Walker’s book you will also know that you are at greater risk of dying in a car accident, developing cancer, Alzheimer’s disease, cardiovascular disease, stroke, and congestive heart failure. Additionally, you will be more prone to major psychiatric disorders such as depression, schizophrenia, and suicidality, as well as more likely to gain weight, become diabetic, and suffer from general loss of memory and cognitive function. 

If these daunting statements discourage you from reading any further, I recommend you try to resist and give the book a chance, as over the following chapters you will find yourself immersed in the wonders that sleep does to our bodies as we are lying unconsciously in the safety of our beds. 

Coming from a background in neuroscience and neurophysiology, Dr Walker had been investigating the differences in brainwave activity of patients with different types of dementia for his PhD, which eventually led him to his career in sleep science. In his first book, Why We Sleep, published in 2017, he is now trying to bring the concept of sleep closer to the broader public and raise awareness of one of the most fundamental processes in the living biological world. 

Starting with the general principle of our circadian rhythm, the reader is being introduced to the mechanisms of our internal clock. The night owls amongst us will be happy to hear that their preference of late-night activities is indeed genetically determined and that they are right to complain about our societal norms and work ethics putting them under great risk of ill-health. The different types of sleep and why all of them are important, as well as their evolutionary context is discussed. Noting that sleep can be found amongst virtually all living animals on Earth, Dr Walker points to the conclusion that there must be a profound biological reason for it. He even connects the adaptation of our primate ancestors from living primarily in trees to becoming ground sleepers, to an increase in the stage of sleep, when we are fully immobilised and a simultaneous decrease in the total amount of sleep to be less at risk from ground predators. 

There are two stages involved in sleep: non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM sleep is also referred to as deep sleep, during which our experiences from the day are shifted from short to long term memory and various regenerating, immune strengthening and cleansing processes are active. REM sleep refers to what may be known as dream sleep. After our memories are put into long-term memory storage, REM sleep then takes over to connect those with pre-existing ones, putting them into a larger picture. This is also the stage of sleep which fuels our creativity and ensures proper processing of our emotions and traumas experienced throughout wakefulness (remember the increased feelings of emotional distress and mood swings after a night of short sleep I mentioned in the beginning? You can now blame your loss of REM sleep for this). Again, Dr Walker jumps in and suggests it is partly due to this increase in REM sleep our ancestors experienced, that ultimately “helped enable the creation of large, emotionally astute, stable, highly bonded, and intensely social communities of humans.”. Thus, without sleep, humans would not have been able to build the foundations for the societal and cultural practices we have today, which are founded on strong social interactions and emotional connection. 

Many of us are aware of the saying that you should get some good rest before an important exam, when you are ill or that you should probably not engage in digital late-night entertainment immediately before bedtime. And yet, we often find ourselves pulling all-nighters, going to work even when we are unwell, watching yet another episode or scrolling endlessly through emails and social media at night.  Dr Walker refers to this as the “sleep loss epidemic” which we are currently living in. With medical care getting increasingly better and more and more people listening to scientists about health and wellbeing, sleep is still being neglected and mostly seen as an optional lifestyle luxury. However, looking at the data, we need to regard sleep for what it is: a non-negotiable biological necessity. Our day-to-day practices of early work times, late night shifts and digitalised communication are disrupting our normal biological clocks and rhythms, bringing ourselves more and more out of touch with our bodies and natural instincts. 

In his first book, Walker guides us through the world of sleep with scientific expertise and facts, but also a good portion of intelligent wit and humour. While mainly focussing on the health and financial impacts of our sleep deprivation on society, Dr Walker also briefly turns to clinical sleep disorders such as insomnia, somnambulism (e.g.sleep walking, sleep talking) and narcolepsy, laying bare how devastating sleep disruption can be, and reminding us to value sleep if we are the lucky ones not affected by any of these conditions. 

This may seem like a very bold statement for some, but after having read the book, you will surely never deny the importance of a good night’s sleep anymore. Paying more attention to the quality and quantity of sleep we get every night could help us fight ageing, mental and cognitive decline, improve our overall fitness, increase our resilience to infections and injury, decrease the risks of getting cancer or cardiovascular disease and make us more ethical as a collective society. 

Read the book before bed and you will treasure every minute of rest like never before. 

For those who are not the biggest fans of reading, I would suggest listening to the Rich Roll Podcast with Mathew Walker (Neuroscientist Matthew Walker On Why We Sleep Is Your Superpower https://open.spotify.com/episode/0MljXuOG7qslyJgKnhQ0Sm) or even sparing only 20 minutes and having a look at Walker’s Ted Talk on his sleep research (https://www.youtube.com/watch?v=5MuIMqhT8DM) – trust me, you will sleep much better afterwards. 


WALKER, M. (2017) Why we sleep. Penguin Books, London. 

THE RICH ROLL PODCAST (2021) [Podcast] May 2021. Available from: https://open.spotify.com/episode/0MljXuOG7qslyJgKnhQ0Sm. [Accessed 08.03.2022]

TED (2019), Sleep is your superpower: Matthew Walker. [online video] Available from: https://www.youtube.com/watch?v=5MuIMqhT8DM. [Accessed 08.03.2022]

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: