Review & Key Findings: Why We Sleep by Matthew Walker

We spend almost a third of our lives asleep yet for most people it is a mystery what happens, why we sleep and why it is so important for you. In this article you will discover why the best selling book of Matthew Walker is a must read and what the key findings are.

The reason that Why We Sleep is a must read

The main reason that this book is a must read is because it explains perfectly what the importance of sleep is. We all know that we need sleep yet we almost always put sleep second. The consequences of not sleeping enough are serious and should not be underestimated. In the long run, sleep deprivation can lead to a higher blood pressure, blood sugar and even weight gain, according to research.

3 Key Findings from Why We Sleep

The book is full of information that will help you understand why we sleep and how you can improve your night of rest. Below are the three points that I found to be the most insightful.

1. You cannot catch up on sleep

We might think we can snatch an hour of sleep every night to make room to do just a bit more. Especially when studying, we tend to stay up late to study or party. So it is not weird to imagine that a lot of people in their twenties don’t get enough sleep. 

Research has shown that two out of three people do not get the recommended 7 to 9 hours of sleep per night. But how do you know if you don’t sleep enough if you think you feel just fine? If one of the two situations below feel familiar, start thinking about your sleep quality and/or quantity

You are likely not getting sufficient sleep quantity and/or quality if you wake up in the morning and already feel tired at like ten or eleven. Another sign is that you desperately need coffee before noon. If you need that to stay awake you are most likely self-medicating your state of chronic sleep deprivation.

We often think that it is okay to sleep less during the week and that we can catch up on sleep on the weekends. However, this is not the case at all. Sleep is not like a debt that you can pay back later. The consequences of sleep deprivation are real and should not be underestimated. Whenever you think that you catch up with sleep, realize you can’t!

2. Morning and evening types are a real thing!

We’ve all heard it many times before: ‘Morning and evening types are not a real thing’. Well, it turns out it is! The start and stop times of people’s inner clock vary widely according to Matthew Walker. This means that we can roughly categorize people as a morning type, evening type and somewhere in-between. Knowing what kind of a person you really are can have an enormous impact on your life!

Or society is built around morning types, which is reflected in school and office hours. However, only 40% of people are early birds and profit from this morning orientated society we have built. 

Roughly 30% of people are evening types.  Their inner clock gives them a natural urge to stay up late and therefore wake up later the next morning. Next to this, their brain also doesn’t wake up quickly in the early morning, for this they need some time to become fully alert and functional. The final 30 percent of people fall somewhere between the morning and evening types.

Over the years people tend to switch from being evening types to being morning types or the other way around. It is heavily dependent on the ritme you have but also depends on the phase in your life. Older people sleep less and go to bed earlier than adolescents.

3. Best phases of sleep to wake up

Another very insightful finding from Matthew Walker is the way he describes the different phases of sleep a person has. We have 4 phases of nREM sleep followed by REM sleep. These can be separated in four stages and phase 3 and 4 of nREM sleep are one stage.

The first phase is nREM stage 1. This is the transition phase between being awake and falling asleep. This phase lasts around 5 to 10 minutes. After this comes nREM stage 2, in this 20 minute phase the body temperature drops and heart rates begin to slow down. 

After this comes the stage where the deepest sleep occurs called, nREM stage 3. This is followed by REM sleep. REM sleep stands for Rapid Eye Movement sleep. This is the phase where you have a lot of brain activity and dream. On the other hand, this is the phase where the rest of your body becomes relaxed and immobilized. This phase is about 60 – 90 minutes long

During a night of sleep, we go through this cycle about 4 times. The worst time to wake up is when you are in the middle of REM sleep. When you wake up in this phase will leave you feeling unrested upon waking up. The best phase to wake up in is nREM stage 2. 

A few quotes worth mentioning

Practice does not make perfect. It is practice, followed by a night of sleep, that leads to perfection.

~ Matthew Walker – Why We Sleep

Inadequate sleep – even moderate reductions for just one week – disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic.

~ Matthew Walker – Why We Sleep

Sleep is the single most effective thing we can do to reset our brain and body health each day – Mother Nature’s best effort yet at contra-death.

~ Matthew Walker – Why We Sleep

Ten days of six hours of sleep a night was all it took to become as impaired in performance as going without sleep for twenty-four hours straight.

~ Matthew Walker – Why We Sleep

Humans are not sleeping the way nature intended. The number of sleep bouts, the duration of sleep, and when sleep occurs has all been comprehensively distorted by modernity.

~ Matthew Walker – Why We Sleep

About Matthew Walker

Matthew Paul Walker is an English scientist and professor of neuroscience and psychology at the University of California, Berkeley. He is a public intellectual focused on the subject of sleep. He became a public intellectual following the publication of Why We Sleep, his first work of popular science, in 2017. It became an international bestseller.

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