Table Of Content

By the Same Author Boivin, D.B., and A. Shechter. “Light and Melatonin Treatment for Shift Work.” In Encyclopedia of Sleep, ed. Clete A. Kushida. Amsterdam: Elsevier Press (forthcoming). Boivin, D.B., and A. Shechter. “Light Therapy.” In Encyclopedia of the Neurological Sciences, 2nd edition, eds. M.J. Aminof and R.B. Daroff. Amsterdam: Elsevier Press (forthcoming). Boivin, D.B. “Jet lag.” In Encyclopedia of the Neurosciences, ed. Kate Miklaszewska-Gorczyca. Amsterdam: Elsevier Press (forthcoming). Boivin, D.B., and P. Boudreau.“Les troubles du sommeil et des rythmes circadiens.” In Les troubles du sommeil, ed. M. Billard and Y. Dauvilliers. Paris: Masson, 2011. Boivin, D.B. “Disturbances of Hormonal Circadian Rhythms in Shift Workers.” In Neuro—endocrine Correlates of Sleep/Wakefulness, eds. D. P. Cardinali and S. R. Pandi-Perumal. New York: Springer, 2006. Boivin, D.B., G.M. Tremblay, and P. Boudreau. Les horaires rotatifs chez les policiers :étude des approches préventives complémentaires de réduction de la fatigue. Montreal: Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 2010. Boivin, D.B., and F.O. James.Prévention par la photothérapie des troubles d’adaptation au travail de nuit. Montreal: Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 2002. Boivin, D.B. “Comment réduire les effets négatifs du travail de nuit sur la santé et la performance ?” Gestion (HEC Montreal) 35, no. 3:47-52, 2010. I dedicate this book to Johanne, who has always been by my side, and to Guillaume, my steadfast companion. To my parents for all the love they gave me. To Catherine and Christine for their invaluable advice. Thank you to all my friends for the evenings of wining and dining. Thank you to all the employees and enthusiastic students at the Douglas Institute’s Centre for Study and Treatment of Circadian Rhythms. Table of Contents Sleep and You Dedication Contents Foreword Introduction Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Conclusion About the Author Credits Foreword Sleep is a part of everyday life and the subject of familiar expressions — “Good night,” “Did you sleep well?” — but it’s also a topic we are asking ourselves more and more questions about. Long a little-explored frontier of the neurosciences, our understanding of the mechanisms that control sleep has made remarkable strides in recent decades. Paradoxically, in the same period, a relatively new behaviour pattern has become widespread in industrialized societies: partial sleep deprivation that, day after day, lets us work longer hours, stay up later to amuse ourselves, and increases the time we spend on activities, right to the limit of what is tolerable. Thanks to artificial light, modern man has gradually developed this uniquely human behaviour pattern: no other mammal chronically deprives itself of sleep. Yet while this behaviour pattern is abnormal in terms of our biology, it is still often admired and envied! Nonetheless, fatigue, difficulties in concentrating, the feeling of being inefficient and in a bad mood — the price paid by many for hours stolen from sleep — make us wonder: Is a manager who boasts about only getting four or five hours of sleep a night a hero or a fool? To shed light on this complex and fascinating subject, Diane B. Boivin has written a rigorous book dealing with ideas on the cutting edge of current neurological and chronobiological research. In it she explains, in a clear and easily understandable way, why quality sleep is essential for good mental and physical health. Many years ago, I tried to persuade Diane to come and work in my laboratory at the University of Chicago. In the end, she chose Harvard, where she made her way flawlessly through a highly charged environment, followed by a brilliant career at McGill University. The invitation to write the foreword to her first book written for the general public stems from years of respect, admiration, and friendly collegiality. It gives me the opportunity to briefly touch on my “pet subject” — the interactions between endemic sleep debt and the obesity and diabetes epidemics. Since we sleep less and less, it’s becoming more and more important to understand just how disastrous the consequences of inadequate or poor-quality sleep can be. My laboratory has been focusing on this subject for nearly fifteen years. Our initial results have encouraged other teams to explore the close years. Our initial results have encouraged other teams to explore the close connections between sleep, hormonal regulation, and cardio-metabolic risk. It’s now well established that insufficient sleep has harmful effects on the hormones involved in appetite control. Limiting sleep time to four or five hours for less than a week leads to an appreciable increase in resistance to insulin, a hormone that is key to regulating glucose and lipids. Short sleepers do exist and are described as people who manage to function reasonably well, both biologically and psychologically, on six hours a night or less, night after night. But these individuals appear to represent less than 10 percent of the population. In reality, many people who say they are short sleepers need more sleep than they think they do. The overall message of more than a hundred studies is that most adults need at least seven hours of sleep to stay biologically and psychologically healthy. Perhaps in twenty years’ time improvements in our understanding of sleep will have helped change people’s perceptions, making them see that sleep is as important as proper nutrition and exercise and that it’s essential to give it the attention it deserves. This book makes a major contribution and is well documented using the most up-to-date sources. The author’s straightforward and lively style makes it a delight to read — and I guarantee it will keep you awake! Thank you, Diane! Ève Van Cauter, Ph.D. Frederick H. Rawson Professor Sleep, Metabolism and Health Center The University of Chicago INTRODUCTION What Happens in the Bedroom? Movement is the very essence of life. I love the seasons — snow falling, melting, and falling again, the alternation of day and night and, of course, waking and sleeping. The sleep-wake cycle has always intrigued me; it is, after all, one of our body’s fundamental rhythms, just like our heartbeat or breathing. When I think about this rhythm and ways to keep it steady and strong into old age, I find myself dreaming once more of the mythical Fountain of Youth ... A scientist’s whimsical thoughts aside, sleep is still a fascinating state, full of mysteries and surprises. This book, not unlike deep-sea diving, is an exploratory journey into the depths of sleep. I’m offering myself as your guide on what is nothing less than a journey through its reefs! Then, when the great white shark of frustrating sleepless nights pounces on you, even though you may have to face it alone, you will have a better idea of how to fend it off. Chapter 1 describes what sleep is, what it consists of, and how it’s studied. The brain works differently depending on whether it’s asleep or awake. The logic governing sleepers’ behaviour is very different from the logic in control when they are awake. Activities performed when you are awake will influence the regions of the brain calling for more rest. Thus, your waking state has an effect on your sleep. Both are part of a sleep-wake cycle and are influenced by a biological clock located deep in the centre of the brain. Chapter 2 describes the biological rhythms called circadian rhythms and the disruptions that affect them. Sleep, in turn, influences your waking state. In fact, sleeping is essential if you want to be wide awake and function properly the next day. The older you get, the more you will appreciate the benefits of sleep and the impact of missing a few hours. Changes in sleep throughout life are discussed in Chapter 3, where we’ll see that sleeping well helps us age better. Chapter 4 is devoted to insomnia. It describes the causes and offers advice to ease the burden. A lack of sleep causes us to eat during the night, and sleep is closely related to diet, metabolism, and weight control. The saying “they who sleep forget their hunger” is true: this is the subject of Chapter 5. Establishing good sleep hygiene is beneficial for both physical and mental health. Chapter 6 describes sleep is beneficial for both physical and mental health. Chapter 6 describes sleep disturbances in various psychiatric and psychological disorders, including depression. A tendency to sleep that’s too strong and extends into our periods of activity is known as daytime sleepiness. Chapter 7 deals with this subject and its clinical management in patients suffering from it. Nighttime breathing problems, largely responsible for daytime sleepiness, are the subject of Chapter 8. And sometimes the line between sleeping and waking is so fine that the two become confused in a borderline state of consciousness. Chapter 9 describes restless sleep disorders typical of such states, as well as motor problems during sleep. This book is intended to be both an overview of the latest discoveries about sleep and a guide to help you sleep better. The hectic rhythm of modern life often — too often for some (including the author) — leads us to burn the candle at both ends. We learn very young to “live on credit” by borrowing, day after day, a few hours a week from the gods of slumber. At first glance, this reserve of hours seems to be unlimited, even free, and, because we are young, we tolerate fewer hours of sleep without experiencing repercussions on our performance in school or in our social life that are too severe. Or at least, so we think! I hope that reading this book will convince you of the opposite and of the benefits of sleep, but especially that it will provide you with useful advice. A solid understanding of what sleep and waking are and what plays a role in disrupting them is crucial. Remember that the source of the Fountain of Youth is a spring at the foot of the tree of knowledge. And just like the water from that spring, sleep too has powers of regeneration.