Why We Sleep: The New Science of Sleep and Dreams (or simply known as Why We Sleep) is a 2017 popular science book about sleep written by Matthew Walker, an English scientist and the director of the Center for Human Sleep Science at the University of California, Berkeley, who specializes in neuroscience and psychology. In the book, Walker discusses about the importance of sleeping, the side effects of failing to do so and its impact on society.
Walker spent four years writing the book, in which he asserts that sleep deprivation is linked to numerous fatal diseases, including dementia.
Why We Sleep has gone on to become a bestseller under The New York Times and The Sunday Times that discusses the topic of sleep from the viewpoint of neuroscience. The book has received generally positive reviews from critics, who praised Walker's research and views on the science of sleep, while criticizing the book for its certain claims regarding sleep.
Background
According to Walker, who had never written a book at the time, he was motivated to write the book after an encounter with a woman who glanced at his work related to sleep and its benefits for health, stating, "When that comes out, I want to read it". Walker described this encounter as a sincere "independent ratification" that made him write the book. The book took Walker roughly four and a half years to write. Walker and his team spent roughly 20 years studying the rejuvenating ability sleep has. Walker's communication style, in which he makes use of "metaphors and analogies effectively," allowed him to explain ideas related to sleep in detail.
At 18 years of age, Walker, who was a medical student at the time, became an "accidental sleep researcher" and moved over to studying neuroscience because of his habit of asking many questions. It was during his PhD at London's Medical Research Council when Walker learned about how little information there was on sleep. A scientific paper helped Walker with his research after his failure to determine the differences of brainwave activity between various dementia found in people, with the paper's contents describing the areas of the brain each variant of dementia attacks. It was then Walker realized that in order to measure his patients' brainwave patterns properly, they need to be asleep. Walker spent six months teaching himself how to set up his sleep laboratory, which allowed him to voice his findings on sleep differences amongst his patients.
Walker noted that many people misinterpret the amount of sleep they actually receive, likely caused by deep thought during the light sleep phases. Following the release of the book, Walker went on to describe his book as having the potential to make readers sleep and jokingly admitted to being concerned to hear if his book kept people awake at night.
Contents
The book is written from a neuroscientific view and is mainly devoted to discussing about the impact sleep has on the functions of the human brain. The book is divided into four parts, each section focusing on how sleep works, its benefits, the reason why dreams occur and sleep issues surrounding society. The book is written in a way so that it does not need to be read sequentially. In the book, Walker discusses about the effects of the widespread effect of sleep-loss, in which the goal in mind being that readers will endeavour in achieving eight hours of sleep once they learn about the connection sleep loss has to other health issues, such as Alzheimer's disease. Other details about lack of sleep explained by Walker include adults who sleep for less than 6 hours at the age of 40 and above have a higher chance of suffering a cardiac arrest or a stroke during their lifetime.
"Sleep pressure and circadian rhythms", the driving forces and the framework of sleep, are brought up by Walker in the book. Other sleep behaviors, such as non-rapid eye movement sleep and rapid eye movement sleep, and the impact sleep has on "synaptic pruning" and the creation of memories during a human's lifespan are also covered. NREM and REM are further explained by Walker to be the two sleeping basics, with 5 cycles present in a person's good night sleep. The book mentions about "morning types" and "evening types" of people, with Walker writing about how spending fewer amounts of time sleeping benefited earlier human predecessors who slept in groups of people due to their time period being safer than now.