Bad night of sleep? The consequences could be worse than simply being a little groggy. Similarly, the benefits of getting enough quality sleep are limitless.

Book Review: Why We Eat: The New Science of Dreams and Sleep, Matthew Walker.

This book covers over twenty years of research carried out by the author and many other researchers investigating why we need sleep and the consequences of not getting enough. I think that this book is a must read for everyone, from parents to politicians.

Sleep has always been important to me, but recently I’ve been getting less of a feeling of rest from my sleep. Am I pushing things too far? Staying up late and then rising too early? According to this book, yes.

I use a FitBit to track my sleep. It divides the night’s sleep into deep and light sleep, REM sleep (rapid eye movement or dreaming sleep), and periods of wakefulness. But what do these terms mean and what are the consequences of not getting enough of one type? Why We Sleep answers those questions.

The answers are scary to say the least. Here is a non-exhaustive list of what can deteriorate with lack of sleep: ability to concentrate, ability to memorise facts or skills involving hands and body, ability to control emotions, immune system defensive capabilities, being able to stay awake during the day.

The latter is a key one that is repeated. If you do not get enough sleep then you may fall asleep, even for a few seconds only, during the day. If this happens during an afternoon meeting, there is not much of a consequence unless your boss gets annoyed. However, should this lapse happen while driving a car, the consequences can be disastrous. Do not drive when short on sleep.

The book backs up each consequence of sleep deprivation with evidence from one of more studies, and so can be heavy on details at times. The author quips that he will not be offended if you fall asleep while reading. I found the topic so riveting that this level of detail did not bother me.

Note that I used the production to listen to the book, mostly while walking, so had no opportunity to doze. The edition was narrated brilliantly by John Sackville.

There is a lot of discussion about testing on animals, which can be difficult to hear about. Be aware of this before reading or listening as it may not be suitable material for everyone.


The age that you are dictates the type of sleep you need most, the amount of sleep you get and also what time of day sleep is best suited to. Teenagers are meant to go to sleep later than normal adults and sleep on into to morning by a biological effect of a slightly different circadian (internal daily clock) rhythm, and any attempt to change them can result in sleep deprivation for the teens.

The knock on effect is an inability to learn or concentrate, mood swings and general unhappiness in the family. Depression is a major side effect of sleep deprivation.

The old aged are another group that can be affected by sleep loss. Evidence is cited for the earlier onset of brain degenerative effects such as Alzheimers disease following prolonged periods during which adequate sleep is not achieved.

Adding to the problem is the increased difficulty older people sometimes have dropping off to sleep and interruptions due to an increased number of bathroom visits. The book outlines some advice for how to alleviate some of these issues without resorting to the pill bottle.

Unborn babies go through a whole cycle of different sleep needs all the way through their early development until young versions of adults. There is evidence linking onset of some brain disorders to lack of sleep for infants but more research is required. This could be scary reading for parents of young children, especially those who have difficulty sleeping.

Adults are not immune to the effects of the lack of sleep. In broad terms the book concentrates on this group of the population citing a lot of experiments on both animals and human volunteer groups.

If you read the book you will learn about N-REM, or deep sleep, how it is the first port of call you will visit each night, and it is the calmest period of sleep in terms of brain activity. This is where memories from the day are sorted and either moved to more permanent memory or dropped.

A good example of the value of N-REM sleep is that given for pianists. Getting a good night sleep including plenty of N-REM after practising a new, difficult piece of music has been shown to improve playing in the morning.

REM sleep is where we dream and several chapters are devoted to this including many of the benefits. More and more is being found out about REM sleep all the time and this is a fascinating field for new research.

Which is more important, N-REM or REM sleep? The fact is that both are needed equally. The author cites a study showing how the brain tries to catch up both categories of sleep. The first night after sleep deprivation you will get more N-REM sleep, and the next more REM sleep. Your body maintains a balance between these provided you give it the chance to get enough of both.

Disease, Fitness, Health and Well-being

The causal links between lack of sleep and a wide variety of diseases is shocking to read. Who could have thought that Alzheimers disease, cancer and heart conditions can all be made worse by not getting enough quality sleep at night.

Athletic and sporting teams are beginning to employ sleep therapists to assist with the coaching of their athletes and players, given the amount of research into how physical conditioning and strength depend on sleep. Coaches may no longer be asking their charges to awake early, losing some vital parts of sleep, in order to get extra training done, if they heed the advice. The cost may be higher than any perceived benefits.

For those of us who like to stay healthy, both physically and mentally, losing even a few hours of sleep regularly over a short or long period of time can have drastic effects on a variety of health related areas.

Choosing what to eat and when can be affected by too little sleep; our decision making abilities are impaired and studies show that junk or convenience food gets chosen after missing sleep, as if somehow willpower is related to a good night of rest. If you want to lose weight, make sure you get to bed on time.

The immune system is hurt by even short periods where not enough shut-eye is had. The effects can last for up to a year. This means that you have less ability to resists virus’s such as colds and other infections. Research has shown how the influenza vaccine is less effective on subjects that have not had adequate sleep.

To me the most worrying research is the effect on emotional state. Studies have shown the loss of the ability to control emotions, causing wide fluctuations in the reactions to emotional stimuli, whether positive or negative. I have experienced this myself; after a poor night, I am more likely to become angry even at the merest provocation.

The author himself has broken ground with the treatment of Post Traumatic Stress, by linking poor sleep around the time of the incident with the continuing re-experiencing of the event. This in turn makes sleep impossible and the cycle continues. The good news is that a possible treatment is undergoing testing.


The evidence in the book is life changing. You will never take sleep lightly again. Indeed it will fill you with concern about how wider society has drifted into simply accepting the poor quality and lack in general of sleep.

It explains why there are so many collisions on the road, so many medical mistakes and why so many children find themselves unable to learn skills and facts in school. What can we do about it?

Education is the first step. First, educate yourself and protect your own and your family’s sleep. We need to teach our young how important nightly rest is and this should rank alongside teaching them about the dangers of drugs and unsafe sex. Poor decision making goes hand in hand with poor sleep practices.

In the USA the issue of early school start times is a major concern, especially for teens. It is not as bad in Europe, but teens are often pressurised into arriving in school early for sports training or other extra-curricular practices. The fact that this can be detrimental and indeed counter-productive needs to be highlighted.

Another problem in the USA is that of the medical doctor intern programme in which medical practitioners need to undergo years of training in hospitals with little time for sleep, working long shifts with not enough time to rest between them. As patients we need to be aware that tired doctors make mistakes, life-threatening mistakes. If you are about to be treated by a doctor, you should inquire about their recent rest before accepting treatment.

Radical policy change is needed from our own individual lives to governments and international relations. I suspect poor policy decisions regarding the protection of sleep will continue until we lobby families, schools, friends, hospitals, insurance companies, politicians and governments to take sleep seriously.

The health benefits that could be realised will lower the ongoing cost of health cover, especially with an ever ageing population. Businesses will become more profitable. Politicians will make better decisions and laws. Each of us needs to take action. My advice is to start by reading Why We Sleep and first following the steps in the appendix within your own life.

Among the potential benefits: work will become easier, you will catch less colds and recover from them faster, you will have more energy, you will be able to learn things and remember them more clearly, you will come up with new, clever ways to solve problems, you will get more enjoyment out of life, you will not be as hurt by the occasional setbacks that life throws in our path.

When you have experienced the benefits that regular, good sleep gives, I encourage you to play it forward. Help your family and friends join you in the fight to take back and protect sleep. Lobby your politicians to put sleep at the top of the agenda to get them to protect children, workers, medical staff and themselves from the dangers of poor sleep habits.

Good night, sweet dreams.