Why We Sleep: The New Science of Sleep and Dreams

This amazing book begins with an excellent introduction, explaining all the reasons and benefits that we are now learning about the value and importance of sleep, which can take up to a third of our life and over 25 years of existence, to learn why this is such an essential and important thing. We know more about reproduction and other medical factors and their importance and particularly around the main drivers of our life how we eat and how we reproduce but not about why we sleep. Walker explains all the things that we know sleep: - “Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer. Insufficient sleep is a key lifestyle factor determining whether you will develop Alzheimer’s disease. Inadequate sleep—even moderate reductions for just one week—disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic. Short sleeping increases the likelihood of your coronary arteries becoming blocked and brittle, setting you on a path toward cardiovascular disease, stroke, and congestive heart failure. Sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety, and suicidality.” - DEMENTIA: Walker originally came upon the importance of sleep when he was doing studies on different types of dementia. People had different, disordered sleep patterns would indicate which type of dementia and he then realised that the role of sleep could indicate what type of dementia somebody might present. - The cyclical rhythms that we have that give us a time function throughout the day and control a whole range of things like when we sleep or the amount of urine we produce. Cyclical cycles exist in every animal that lives for over seven days, but it also exists in plants and is an essential function to how we live and exist. Interestingly, enough in experiments carried out on the cyclical time factor in our own body cover a 25-hour cycle rather than a 24-hour cycle and this cycle will occur whether we have a plant or a human in a dark place so long as they've already learned these cycles through daylight. - STAGES: Although there is only one stage to being awake, and that is wakefulness, there are four stages to sleep, of which one of those stages is known as REM. which is when you are most prone to dreaming, and whilst you're in the stage, your body is paralysed and unable to move. Things such as breathing remain active. - All animals, including things such as bacteria require sleep and yet animals require different amounts of sleep so that an elephant only requires four hours sleep, half as much as humans whereas tigers and lions devour 15 hours of sleep. - All mammals have REM sleep. Having such a large and sufficient REM sleep allows our brains to rationalise emotions and emotional responses and allows us to recognise and make appropriate decisions. Lack of sleep will impact on your ability to rationalism and use appropriate emotions. - MEMORY: There is some fascinating research around memory and how sleep can help improve skills such as motor skills. Once a task is done and looking at people mastering taps in certain sequences on a typewriter, and when they were asked to repeat the test - the amount of sleep you have corrected errors in tapping skills, so that motor memory would improve, but needed sleep to master this skills more effectively. This can be transferred to learning a musical instrument. - Good sleep did not just help motor memory, but it can also help repair and increase sports ability and connections required for plasticity in repairing a brain after stroke, but all of these are requiring sleep both before and after something has been acquired. - LEARNING: Sleep also helps to support creativity and it's as if our brains are given a real work out at night even though we think we're sleeping, it supports making new connections regarding learning and supporting and maintaining a healthy brain. - “Growing scientific evidence now supports the wisdom of later school start times. One longitudinal study tracked more than 5,000 Japanese schoolchildren and discovered that those individuals who were sleeping longer obtained better grades across the board. Controlled sleep laboratory studies in smaller samples show that children with longer total sleep times develop superior IQ, with brighter children having consistently slept forty to fifty minutes more than those who went on to develop a lower IQ.” - DRIVING: Sleep deprivation is one of the most significant causes of accidents in car fatalities, and it's far more prevalent in causing car accidents than drugs and alcohol combined. - An interesting fact about sleep deprivation is that people who become tired, are no longer functioning to their full potential and reduced capacity, and yet the sleep deprived do not seem to be aware that they are incapacitated by the sleep deprivation. However, tests show they have changed in the baseline and ability to perform mental task. - Experiments have shown different stages of sleep deprivation regarding 2 hours, 4 hours and 7 hours and then tests compared to people in stimulated car machines when driving a car when drunk and with lack of sleep. People who are drunk might be late at braking, but people who are sleep deprived begin to have micro sleep and fall asleep at the wheel. This will occur every 30 minutes and in America there will be a car crash due to somebody with sleep deprivation, and in fact, the numbers are even worse than if you drink and drive, although both are seriously bad to be doing. - MENTAL HEALTH: There is no mental health disorder (this includes schizophrenia, bipolar disorder conditions, ADHD, and autism), that doesn’t seem to show that sleep deprivation will always occurs in these conditions. - Conditions like bipolar disorder formally known as manic-depressive has been shown that sleep deprivation will trigger psychiatric element of manic disorder. The author does not make the claim that sleep deprivation is the cause of these conditions but is a factor in what might trigger psychiatric episodes. - AUTISM: There are possible issues around correlation between REM, lack of sleep and autism. In experiments, when rats’ brains have reduced REM sleep, they do become socially aloof and distance from the other rats. - DEMENTIA: There is also an important link between sleep deprivation or lack of sleep and Alzheimer's disease. We know that amyloid plaque build-up occurs in the brain and if you have a full night deep sleep, these are washed away by cerebrospinal fluid and this allows the brain to function properly, but lack of sleep will impact on the cleaning operation where the brain is flushed several times during the night to promote healthy brains and reduce the risk of Alzheimer's. Sleep deprivation has been looked at both in assessment and diagnosis in supporting those in reducing the risk of Alzheimer's. We have at least 4 to 6 cycles of deep sleep in a full night’s sleep. - HUNGER: Sleep deprivation impacts on a hunger hormone, as well as increasing blood pressure and forming increased risk of diabetes. When we are hungry, we have hormones called ghrelin, which will impact on helping us to feel hungry and leptin hormone, which let the brain know that our body is full. But when sleep deprivation occurs, these hormones become altered and ineffective in regulating the metabolic state of the body so that when we are sleep deprived, we also tend to eat more type of carbohydrate type foods, junk food and confectionery. - When we are tired, we tend to eat more carbohydrate and rich sugary-based foods than when we are fully rested from the good night sleep. MRI studies have shown that there are parts of the brain that switch off and we only want protein-based foods and sleep deprivation is a perfect cause of increasing obesity, as we will eat more rubbish-based foods and the brain areas that would want you to eat more healthy based foods are switched off so that you want to eat richer, sugar-based foods. - Although lack of sleep is not the only factor in weight gain, it has been shown that lack of sleep does correlate with increased weight. - OBESITY: Children aged 3 who sleep less than 10 ½ hours or less have a 45% increased risk of being obese by age seven than those who get twelve hours of sleep a night. “Short sleep will increase hunger and appetite, compromise impulse control within the brain, increase food consumption, decrease feelings of food satisfaction after eating and prevent effective weight loss when dieting.” - MICROBIOME AND GUT HEALTH: Lack of sleep also impacts on the microbiome which is so important in our bodies in making sure we're able to absorb the right types of food, but when sleep deprivation occurs, the Microbiome is impacted on this and works less effectively. It has been shown that there is a two-way correlation between the Microbiome and sleep disorders, but currently we do not have robust evidence. - REPRODUCTION: Lack of sleep impacts on the hormone testosterone which we require for reproduction and for staying alert. Reductions in testosterone amounts leads has a significant impact on how well we can reproduce and the people with less sleep have reduced testosterone. Poor sleep of less than 5 hours in healthy males will reduce from baseline, will have a 29% lower sperm count and the sperm themselves will have deformities. - IMMUNE SYSTEM: Another important factor is how sleep strengthens the immune system. When you are ill, you need to sleep, and that is what sleep does in repairing the body and helping it to fight infection. Lack of sleep has been shown to reduce the effectiveness of the immune system, which then impacts on the growth of cancerous cells. Nightshift workers and people who do jobs which disrupt sleep how far greater risk of illness and cancer and has even been cited as the world health organisation (WHO). To be stronger and better we need to sleep. - REM: REM sleep in which we dream appears to be a by-product of neuronal activity as our brain becomes very active during REM sleep, although we are also left paralysed, and it also reduces adrenaline and noradrenaline - which raise heart rates. Adrenaline which often causes anxiety when we're awake but becomes reduced and stopped during REM sleep so that we might be able to work through emotional issues while sleeping. Tests seem to support this. - PTSD: People with post-traumatic stress disorder who were having recurring nightmares that the neuro adrenaline hormone was not being suppressed and thought that if you gave medication that reduces adrenaline, they might stop having post-traumatic stress disorder, nightmares and the same time somebody was prescribing medication which activated on reducing blood pressure but also suppressed noradrenaline and these people stop having nightmares. It's now become a form of treatment in treating post-traumatic stress disorder. - CREATIVITY: REM sleep can make us creative. If you have a difficulty, it is worth dreaming on it or falling asleep because REM sleep will help us to have better periods of creativity. The adage that if you have a problem, sleeping on it can help. - MELATONIN: Melatonin is a hormone to help with sleep but becomes disrupted by staying up late and particularly blue light that you might find in iPads if you read them for an hour or two before you go to bed will impact on your sleep. - ALCOHOL: Alcohol will impact on your ability to learn and disrupt REM sleep, which is so important for learning and emotional control. Alcohol and drugs impact so abstinence is important if you want to have dreams and proper sleep. - CANCER: Sleep deprivation which has been assessed in rats and other animals shows that if you do not sleep, you will die and there are conditions that cause people not to sleep and they will suffer horrible health issues. They're immune system no longer functions properly, and they become ill and die due to diseases such as sepsis that would be otherwise minimal in somebody with healthy sleep. - SLEEPING PILLS: In America in the last month there would've been 10 million people taking prescription sleeping pills and yet these medications are harmful and shouldn't really be used. They are more sedatives than pills to support proper sleep. Walker suggests that the first line of appropriate treatment is cognitive behavioural therapy, which include things like reducing the amount of caffeine and sleep in a regular time. - HOW SLEEP HAS CHANGED: Data over the last century shows that only 2% of Americans were sleeping less than six hours a night and now it is currently almost 30% adult asleep in less than six hours every night. The book looks at how society and sleep are working and interacting. This is having a massive effect on people’s health and well-being and mood. Many people who run businesses will often send-off emails early in the morning and work late, but and this is almost seen as a piece of bravado, but actually the cost to companies where employees are working late and having a less sleep is costing billions to the workplace and the current economies and is actually counterproductive. Companies devalue the importance and they need to start to value sleep. - CHILDREN: Research is shown time and time again that in studies where children start school at later times. There is much higher score points in terms of all subjects and exam examination scores. - ADHD: Children with ADHD are irritable and moodier, The same symptoms that you would see in a child who had a lack of sleep as the same as you would see in a child with ADHD so if children aren't sleeping, they will present with a similar diagnosis or presentation, and if you tell the doctor all the symptoms and you don't mention that the child is having problems with sleep or not sleeping enough, then it may well be that the doctor will diagnose that child as having ADHD. - “The state of chronic sleep deprivation builds over time, the child will look ever more ADHD-like in temperament, cognitively, emotionally, and academically. Those children who are fortunate to have the sleep disorder recognized, and who have their tonsils removed, often prove that they do not have ADHD. In the weeks after the operation, a child’s sleep recovers, and with it, normative psychological and mental functioning in the months ahead. Based on recent surveys and clinical evaluations, we estimate that more than 50 percent of all children with an ADHD diagnosis actually have a sleep disorder, yet a small fraction know of their sleep condition and its ramifications.” - ADHD MEDICATION: “Most people know the name of the common ADHD medications: Adderall and Ritalin. But few know what these drugs are. Adderall is amphetamine with certain salts mixed in, and Ritalin is a similar stimulant, called methylphenidate. Amphetamine and methylphenidate are two of the most powerful drugs we know of to prevent sleep and keep the brain of an adult (or a child, in this case) wide awake. That is the very last thing that such a child needs. Dr. Charles Czeisler, has noted, there are people sitting in prison cells, and have been for decades, because they were caught selling amphetamines to minors on the street. However, we seem to have no problem at all in allowing pharmaceutical companies to broadcast prime-time commercials highlighting ADHD and promoting the sale of amphetamine-based drugs (e.g., Adderall, Ritalin). To a cynic, this seems like little more than an uptown version of a downtown drug pusher.” - Children who have apnoea where they have problems with sleeping and it's causing them to wake and when surgery is used to correct this procedure and reduce lack of sleep in episode, these children symptoms of ADHD disappear. - The book argues that up to 50% of children who might have been presented with the symptoms of ADHD, have actually got sleep disorders or don’t sleep sufficient amount and they're having blue light on before they go to bed from their iPads and that's causing them to sleep yet. Many parents are unaware of this regarding ADHD. - Someone who has impaired sleep can have a similar level of behaviour as someone who is drunk and doctors and particularly new junior doctors who to do excessive amounts of training without sleep and do long 13 hours straight. Many doctors are after finishing long shift are 168% more likely to be involved in a car crash than others who aren't. - The effectiveness of a vaccine such as a flu vaccine is dramatically reduced because we need to sleep to help the vaccine work at its most effective and efficient rate. Some of the ideas to support sleep do include analogy that allows us to maximise the effectiveness of sleeping patterns in individuals and society. - Most children have had some form of education, around diets, the importance of exercise, the importance of vaccines and diet, but almost, no one has had any education or been provided information around the importance of sleep, excise, the food we eat, etc. and this needs to change. - PAIN: Another interesting fact that sleep deprivation is it when this occurs you will feel increased amount of pain and you would otherwise feel if you had a full night sleep. - NEONATES: A good night sleep can act like an anaesthetic in the same way as morphine and actually target the areas in the brain that such sedatives also impact on, but without all the harmful side-effects that you would associate with the kind of medicine such as morphine. And yet in hospitals, it's one of the most ineffective places to get sleep due to the constant beeping and noise levels and yet here we are once again causing more harm on individuals and reducing their ability to manage pain through reduced sleep patterns that are clearly associated with hospital stays. - END: Who would've thought that a book about sleep could be so eye-opening, and that a book about sleep could keep you awake with so many extraordinary facts and information about how important sleep is in so many ways, both in supporting our health, stopping us from feeling ill, impacts on our ability to think or concentrate or learn and the importance of something that takes up a third of our lives is only now being realised. This is a remarkable book.

This is a fantastic book about sleep and all connected to it. It spent about a year on my bedside table because every evening when I opened it while in the bed, after 1-2 pages I realised that it was better to put it back and fall asleep as soon as I could, rather then read it. What an irony. The book is extremely well-reseached. The author - being a leading scientist in the field - explores every side of our lives such as health, education, efficiency at work, mental health, emotional state, length of lives etc and how they are impacted by sleep and by lack of it. The book starts with 30-50 pages of scientific information about sleep - different stages, brainwaves, sleep of animals etc etc. For less scientifically curious it can be a boring bit but if they manage through, they will be rewarded with absolutely solid knowledge. I am - as many of us - a bit of sleep-deprived for many reasons: children, technology, early mornings to be at work, and silly habit of trying to read books in the bed. It is not a secret that sleep is good for us but we still play games with it. Reading this book convinced me that sleep is crucial for all aspects of my life, and of my children and family. We often see some celebrities or executives on TV who insist that their 4 hours of sleep a night is enough for them. After reading this book I don't believe them any more. No more I am surprised and impressed by them - I rather pity them and their families and subordinates. I strongly disagree with reviewers who say that the book doesn’t have advice what to do. The advice is simple and one doesn’t need to read a book of 300 pages: give yourself a favour and sleep more. We all know details: cut on caffeine, don’t drink alcohol, keep your bedroom filled with fresh air etc etc. The use of this book for me is not that pieces of advice but understanding why it is so important to sleep enough. And, by the way, author gives a lot of advice through the book, and as a summary at the end. Very useful and life-changing book. But don’t expect magic advice like “if you don’t sleep enough, try doing this instead”. There is no shortcuts for good sleep. Good night!

Why We Sleep is a good book. Matthew Walker has attained mastery in the field of sleep due to his intense love and studying of the subject for so many years, and his depth and quality of knowledge is apparent. One thing I learned was about adenosine. Adenosine is a chemical that builds up throughout the day that makes you sleepy. If you have enough sleep, your adenosine levels plummet and go back to zero upon awaking. If you don’t, you carry this ‘sleep debt’ over into the next day, which is a not a good way to start your day for muultiple reasons. Also, you never actually recover lost sleep. Another thing that will stay with me forever is the post-prandial dip in alertness, which is the dip in energy levels mid-afternoon. This is something all humans experience, which for someone who lives a healthy lifestyle consisting of a good diet and daily exercise, soothed some of my frustrations as to why I still experienced this. A way to combat this is a nap before the onset of the energy dip. Some of the largest companies in the world such as Nike, Google and NASA recognise and incorporate this, and so will I. A good quality and quantity of sleep is also important for effective weight management. If you’re trying to lose weight, sleep well, and you lose more fat and keep more lean muscle. Sleep poorly, you lose less fat and lose more muscle. However, as I progressed through the book, I found it harder to stay focused, as it was mainly Part 1 and 2 that I was interested in. Overall, the core message of the book is that sleep is SO important, in more ways than you can possibly comprehend.

I can't say anything about the book yet, I'm sure it's good... But I was upset by the condition it arrived in. It's sticky and scratched. It looks as if it's already been read, and it's unpleasant to hold. The price was ok, otherwise I would return it straight away

Lettura estremamente interessante ed educativa: esaustiva, dettagliata, con decine di studi scientifici a supporto degli argomenti trattati. Descritto così sembra quasi si tratti di un libro universitario, ma non lo è affatto! L'autore, professore di Neuroscienza e Psicologia e direttore di un laboratorio di ricerca su sonno e neuroimaging, è riuscito a mettere a terra l'argomento in maniera da rendere la lettura interessante, piacevole, e soprattutto di facile comprensione. Sicuramente consigliato a chi, come me, è sempre stato incuriosito dal sonno e voglia saperne di più. Tra gli argomenti più interessanti in mia opinione: cos'è il sonno e dove ha origine, a che cosa serve, come cambia nel corso della vita, quali possono essere gli innumerevoli effetti del dormire poco (ad esempio su apprendimento ed emotività), a cosa servono i sogni, e come sia possibile migliorare il proprio sonno senza ricorrere a farmaci.

What a brilliant book. This has changed the way I look at nutrition, sleep and health.

Que gran libro, si tienes problemas de insomnio o quieres informarte con lo mejor en los estudios del sueño es un libro ideal

This book compiles a lot of scientific findings about sleep. Sleep is essential for our mental and physical health. A lack of sleep can cause many serious problems. I have changed my recognition of sleep entirely. I want to recommend everyone who engages in health care.