Description * Over 200,000 copies sold in the UK * Published in 35 countries worldwide * UK and US Amazon bestseller * New York Times bestseller * Sunday Times bestseller (49 consecutive weeks) * Named a Book of the Year by The Guardian, The Observer, The Financial Times, The Daily Mail, The Evening Standard, Publishers Weekly, and NPR (2017) Why We Sleep by Matthew Walker, the world-renowned neuroscientist and sleep expert, has been translated and published by Open Books. Walker is not only a leading scholar in the field of sleep medicine, having published over 100 scientific papers through his tireless research, but is also widely recognized as a self-proclaimed "sleep diplomat" who actively communicates with the public through television and radio. In this book, the author explains, in an accessible way backed by scientific evidence, the many aspects of sleep that we never knew, drawing on his position at the forefront of sleep medicine research. With remarkable insight, he shows us how the astonishing power of sleep can lead our lives in a better direction. The Science of Sleep and Dreams Humans spend two-thirds of their lives awake. We move about with consciousness, engaging in what we consider productive activities—socializing, protecting ourselves from threats to survival, securing food, and reproducing. The remaining time, when we are unable to do any of these things—that is, when we sleep—appears, from an evolutionary standpoint, to be highly unproductive. And yet we sleep anyway. The fact that every living creature continues to sleep despite this apparent danger clearly suggests that there must be tremendous benefits that far outweigh the risks. Countless studies consistently show that getting plenty of sleep does not exclude us from biological benefits in any way—in fact, there is no reason why we should not sleep. Sadly, humans are the only species that deliberately deprives itself of sleep. The author's argument is clear: we must focus on making the most of the one-third of our lives we spend asleep. Sleep is among the most important yet least understood aspects of our life, health, and lifespan. Until quite recently, science could offer no answers to questions like why we sleep, how sleep benefits our body and brain, or why lack of sleep causes serious health problems. Compared to other basic needs like appetite, thirst, and sexual desire, sleep has remained remarkably poorly understood relative to its quantitative and qualitative importance in human life. Over the past twenty years, an explosion of scientific discoveries has begun to shed new light on this subject. What Do We Gain from Sleep? The benefits of sleep described by the author in this book are truly astonishing. Getting enough sleep strengthens memory and boosts creativity. People who sleep well appear more attractive than those who don't. Sleep helps maintain a slimmer body and reduces appetite. It helps prevent cancer and dementia, and wards off colds and the flu. It lowers the risk of heart attack, stroke, and diabetes. It elevates happiness and dispels feelings of depression and anxiety. Dreaming during sleep eases painful memories from our waking life. The brain even creates a virtual reality by merging past and present knowledge to spark creativity. Sleep and dreams perform countless other functions for our body and mind. For Those Who Have Forgotten the Night How many hours of sleep is ideal for a person? Five? Six? Seven? Consider the typical modern morning: waking up every day with the help of an alarm clock, and drinking caffeine to stay alert. This seemingly ordinary scene is actually a clear symptom of the sleep deprivation seen around the world—the World Health Organization has already declared sleep deprivation an epidemic across the developed world. The US, UK, Korea, and Japan are among the countries where sleep time has decreased the most over the past century, and where the number of patients suffering from physical and mental illnesses caused by lack of sleep has increased the most. We somehow manage to wake up and start our day, but it's hard to shake the feeling of sleep deprivation throughout the day. If calling mild sleep deprivation an "epidemic" seems excessive, consider the following symptoms that occur in our bodies when we don't get enough sleep. Insufficient sleep first damages our immune system. The risk of cancer doubles, and changes that are precursors to Alzheimer's disease and diabetes occur in the body. Cardiovascular disease, stroke, and congestive heart failure can result. Poor sleep worsens symptoms of major mental illnesses, including depression, anxiety, and suicidal thoughts. And as sleep duration shortens, so does lifespan. This is why the author describes sleep deprivation as "a slow form of self-euthanasia." Fortunately, the wealth of scientific data and analysis in this book offers a solution to all of this at once: a completely free natural remedy—getting eight or more hours of sleep. For Those Battling Drowsiness Despite the clear benefits of sleep, we work tirelessly to cut it short. Being an "early bird," escaping the stigma of laziness and weak willpower, or simply keeping up as a modern person—our self-justifications for skimping on sleep are endless. Of course, there are people who are naturally short sleepers. They wake up on their own after just six hours, without an alarm, and don't need to sleep again for the rest of the day. Thanks to certain genes, they can function perfectly well on less sleep than others. People often want to believe they belong to this group—perhaps because their daily lives do involve sleeping little and staying awake long—but in reality, very few people actually fall into this category. The author quotes a colleague to explain why: "The number of people who can survive on less than five hours of sleep without any impairment, expressed as a percentage of the population, rounds to zero." Could we really believe we belong to the less than one percent of people—a probability lower than being struck by lightning in our lifetime? Sleep is the single most effective means of renewing the health of our brain and body every day. And yet, individuals and society alike rarely bring up sleep when discussing health today. Executives and employees who arrive early and work late into the night, far from contributing to their companies, end up causing significant losses due to poor judgment stemming from sleep deprivation. Medical residents working thirty-hour shifts make misdiagnoses and leave surgical instruments inside patients. Drowsy driving causes more accidents than drunk driving, yet the effort put into preventing it is less than 2 percent of that spent on preventing drunk driving. We Must Sleep Almost every question the author raises about sleep in this book perfectly explains why we must sleep. How do caffeine and alcohol affect sleep? What actually happens during REM sleep? Why do our sleep patterns change as we age? How do common sleeping pills work, and what long-term harm can they cause? How do dreams enhance learning, mood, and energy, and regulate our hormones? How is sleep related to children's growth, and to efficiency, achievement, and productivity in the workplace? Written clearly, engagingly, and accessibly, this book will completely transform readers' understanding and awareness of sleep and dreams. Let's make full use of the one-third of our day we spend sleeping—because that is the most effective and complete way to make the most of the remaining two-thirds of our lives.