Book Review
Title: Why We Sleep: Unlocking the Power of Sleep and Dreams by Matthew Walker
Genre: Non-Fiction, Science
Rating: 4.5 Stars
The opening chapter to Why We Sleep was intriguing as it explains that while sleep affects a massive part of our lives and the repercussions, we can face for having less sleep or disrupted sleep, we don’t know why we sleep especially since from an evolutionary perspective it leaves us vulnerable to attack which isn’t a good thing. It is also a feature that is present is every species alive today meaning the need to sleep evolved with us from the very beginning but there are still many mysteries surrounding why we sleep and how we dream which the book aims to break down and explain.
Chapter two looks at the mechanisms of sleep specifically how and why we experience tiredness and wakefulness and what causes it and how these systems can be disrupted by things like caffeine. It was interesting to learn that the circadian rhythm and sleep pressure caused by hormones are independent of each other. This explains why some people sleep at different time than others such as early birds and night owls. It was also a little disconcerting to learn that night owls are plagued by more health issues because they live in a world geared towards early birds and this disruption of their genetically determined sleep cycle can be dangerous over time. Caffeine was interesting to look at especially how it works by affecting the brain since all it does is block the sleep pressure from being perceived despite it continuing to increase and eventually smacking you in the face later during the caffeine crash.
Chapter three goes a little deeper by looking into the different stages of sleep and what they are and what their function is. There are two main types of sleep, NREM and REM. NREM sleep is the deeper type of sleep and in this type of sleep you purge unnecessary information from the brain while in REM sleep you process the information you are keeping and form stronger connections in this time. REM sleep is also the time where we dream, and this can be seen by the lack of muscle tone during this sleep as we are effectively paralysed by our brains to prevent us from acting out our dreams, but this becomes weaker the older we get. While many people will know the information in this chapter coming from a sleep specialist, we get a different insight into sleep and dreams.
The remainder of part one looks at two important aspects of sleep in a larger context. First is sleep across species and the second in sleep and age. Sleep across different species is vast with some animals only needing four hours sleep while others like the brown bat sleep the most as 19 hours. Even the sleeping patterns across the same genetic families is strangely vast. However, there are some distinct differences, for example, all animals sleep but only a select few enter REM sleep and dream. Mammals seems to have this ability except for aquatic mammals like dolphins. Despite not being able to dream animals like dolphins and whales can separate the halves of their brain. While they are awake both halves work in unison but when they sleep one half turns off while the other remains on to keep them moving which is vital for their survival.
Sleep across the age spectrum was also interesting as it focuses just on humans but the difference in our sleep needs as we age is immense. While a mother is pregnant the baby will spend most of the pregnancy asleep with them only being awake right at the end of the pregnancy. During this time, they consume a huge amount of REM sleep which is vital for building the brain which happens to be the last major organ to be formed. From birth into toddler stage, we sleep a lot to grow the brain pathways and the body but as we progress into early childhood the amount of sleep we need decreases but the need for both NREM and REM sleep remains although the ratio changes with time. By the time we reach our teens, the need for sleep grows again and it is coupled with an increase in NREM sleep, this is because we have too many pathways in the brain and a culling takes place of the useless ones done in NREM sleep. This means that teenagers need as much sleep as a newborn does for a very similar reason and it seems to be shown that disrupted the sleep in these vital stages can have major long-lasting consequences. The sleep ratio settles throughout adolescence and early adulthood but slowly declines with age. This isn’t because we need less sleep, in fact, someone in their 80s needs as much sleep as someone in their 40s but they no longer have the ability to generate this sleep since the area of the brain responsible is one of the first to deteriorate and rapidly does so. This means that elderly people typically sleep less and have disrupted sleep leading to lot of issues, but sleep is never seen as the issue.
When we enter part two, we begin by looking at the benefits of sleep. This focuses more on the benefits of sleep on memory, skill retention and muscle memory. Obviously, most people know that we remember better after sleeping but the staggering difference in clinical trials between those that slept and those that didn’t was immense. However, many might not know that this also applies to new skills and muscle memory. Skill retention was an interesting area to look at because when people were presented with a challenge like typing with their offhand, they performed better and more seamlessly after sleeping than those that didn’t. In a similar vein we also look at muscle memory which is misnamed because the muscle doesn’t remember anything, but the brain does. In these situations, the brain retains information on the sequence of movements like the movements your fingers making when playing scales on a piano and because sleeping reinforces and strengths connections, after sleeping these movements become more fluid and require less conscious effort.
The next chapter looks at sleep deprivation and the effects it has on the brain. As someone who used to pull all nighters on a regular basis, I was interested to see what happens inside your brain when you take away the key element of sleep. There are numerous effects that a lack of sleep has on the body but the one the author mentions the most is Alzheimer’s disease. It has been proven through various studies using both sleep and brain scans that the plaque that builds up in the brain causing Alzheimer’s is increased by a lack of deep sleep. This is because the brain flushes out these toxins during deep sleep and as you age and lose the ability to have deep sleep these toxins increase and a lack of sleep at a younger age can make you more at risk of the disease later in life. Lack of sleep also has a major impact on your heart, increasing your risk of heart disease and heart failure by up to 400% in some cases which is insane considering how easily we sacrifice sleep for the sake of other things like work, school and childcare.
The following chapter follows the previous one as it looks at sleep deprivation and its effects on the body rather than the mind. These effects are just as devastating as those on the mind perhaps even more so since we don’t even realise what is happening to our bodies with sleep deprivation. One of the key elements we lose when we lack sleep is the ability to fend of disease as it weakens our immune system to the point where it doesn’t really recover even if you are given weeks of recovery sleep. While this might not seem too important to most given the fact we can cope with things like colds easily, it also hampers the immune system’s role in fighting off cancer. Our bodies usually can deal with a small number of abnormal cells destroying them before they become a problem but with a weakened immune system the likely of these cells being destroyed is lower and therefore increasing your risk of cancers especially in places where abnormal cells are more likely to occur like in the uterus.
The next part of the book brings us back to more light-hearted topics as we begin to dive into the how’s and why’s of dreaming. One of the first things we discovered about dreaming was we have no control over it, and it happens naturally when we enter REM sleep meaning it is required for the body to function normally. The state of dreaming can be observed on brain scans, but it doesn’t explain why or how it happens. it was interesting to see the journey that the study of dreams has taken, from Freud’s psychanalysis to modern methods that have accurately allowed us to predict the subject of a dream through just the brain waves emitted during sleep. While there are still many mysteries to dreaming, we have come a long way in a relatively short period of time.
It has turned out that REM sleep is actually a form of therapy for most people. The science behind this is still relatively unknown but what we do know is during REM sleep the overwhelming emotions we felt at the time of memory creation are removed, this means for people who experience traumatic things it can actually help them cope and move on from the event without having to relive those same emotions every time they review the memory. However, in some people with PTSD, they don’t enter REM sleep for as long meaning they struggle with this emotional detachment are treatments and/or therapies are being developed in order to provide a solution to this in order to treat those with PTSD better.
We see that intelligent information processing that inspires creativity and promote problem solving is drastically weakened with lack of sleep. This is because during the dream state we bring together masses of acquired information and then extract the necessary overarching rules and commonalities meaning we don’t have to remember every minute detail, but this process is impaired when you deprive the brain of sleep. However, during the research on sleep deprivation on memory it was discovered that lucid dreaming is very real. Many scientists have seen the brains of lucid dreamers on scans while they are asleep, but the brain activity is like that of an awake person. This discovery meant that individual could control their dream state mentally, but the implications of lucid dreaming need more in-depth research.
Moving onto sleep disorders, the first thing we realise is they are far more common than many believe. We are taken through some of biggest disorders, including what they are and their effect on the afflicted person. These disorders include insomnia, narcolepsy and fatal familial insomnia or FFI. These disorders especially FFI are extremely damaging as they disrupt or completely alter the ability to sleep. FFI causes death due to lack of sleep because these people lose the ability to sleep altogether and currently there are no treatments or cures for the disorder which is frightening to think about. There is also a comparison between sleep and food deprivation and the damaging effects of sleep deprivation far outweigh those of food deprivation.
The next chapter looks at the things that impact our sleep such as blue light, alcohol, drugs and much more. The biggest factor affecting our sleep in the modern age is blue light especially those from LED sources which are everywhere to the point it is difficult to avoid them. However, without realising they have inhabited our sleeping spaces in the form of phones, computers, lamps and much more which is stopping the rise of melatonin at night and thus preventing you from sleeping. Due to this the topic of sleeping tablets arises, these are not recommended for severe sleep disturbances because they don’t provide true sleep, they provide unconsciousness. This means we don’t get the sleep we need even though you are sleeping with the aid of the medication. We also see there is no proven link between things like diet and exercise with sleep. There is some measure of a bidirectional relationship meaning that sleep will affect your diet and exercise but there is no hard evidence to prove that diet and exercise affect sleep.
Now we look at society and sleep and how most of us are doing it wrong and only a few companies like NASA and Google are doing it right. It is explained that the traditional 9-5 in work environments and 8-4 in educational environments are detrimental to healthy sleep. Work environments often praise those that arrive early and stay late disrupting their sleep schedule when the reality might be it is taking them longer to do the same amount of work because they are sleep deprived. Education has a similar problem since we know teens especially need more sleep and that sleep helps with memory retention, yet we insist on waking these people up in the middle of the sleep cycle leading to poor performance and low memory retention. Another area where sleep deprivation is common and yet lethal is in medicine. Many doctors must do a residency where 30-hour shifts are common, and many suffer with severe sleep deprivation. However, this leads to missed diagnosis, misdiagnosis as well as patient harm and even death.
Yet we insist that this is the correct way to train doctors when the system was implemented by someone with a severe cocaine addiction allowing them to power through the sleep deprivation. These are all things that need to change in society to provide better sleep and thus increase performance, retention and reliability in these different areas. Personally, I believe doctor schedules need to change first because sleep deprivation in this area can cause severe harm and even death. Doctors are more likely to be the cause of car accidents because of microsleeps as they work insane hours without rest. The author even creates a schedule that still isn’t ideal but a lot better than what is currently in place, and it would provide a lot more sleep for doctors without harming the patients involved. This is important since there’s simply no evidence-based argument for persisting with the current sleep-anemic model of medical training, one that cripples the learning, health, and safety of young doctors and patients alike.
In conclusion, there was a lot of useful information about sleep and getting better sleep, but the biggest message in the book is how society needs to change how we view sleep especially in the medical and education sectors to get better performance out of those in these sectors. Overall, if you are interested in the science behind sleep or want some evidence about how to improve your sleep then definitely give this book a read.
Buy it here:
Paperback/Hardcover: amazon.co.uk amazon.com
Kindle Edition: amazon.co.uk amazon.com
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