Back Cover Blurb1
- Sleep is one of the most important aspects of our life, health and longevity and yet it is increasingly neglected in twenty-first-century society, with devastating consequences: every major disease in the developed world - Alzheimer's, cancer, obesity, diabetes - has very strong causal links to deficient sleep.
- Until very recently, science had no answer to the question of why we sleep, or what good it served, or why its absence is so damaging to our health. Compared to the other basic drives in life - eating, drinking, and reproducing - the purpose of sleep remained elusive.
- Now, in this book, the first of its kind written by a scientific expert, Professor Matthew Walker explores twenty years of cutting-edge research to solve the mystery of why sleep matters. Looking at creatures from across the animal kingdom as well as major human studies, Why We Sleep delves into everything from what really happens during REM sleep to how caffeine and alcohol affect sleep and why our sleep patterns change across a lifetime, transforming our appreciation of the extraordinary phenomenon that safeguards our existence.
- Matthew Walker's fascination with sleep has taken him from Nottingham to Harvard and on to the University of California, Berkeley, where he is currently Professor of Neuroscience and Psychology and Director of the Sleep and Neuroimaging Laboratory. He has published over 100 scientific research studies during the course of his twenty-year career. Why We Sleep is his first book.
Amazon Publisher’s Blurb
- The New Science of Sleep and Dreams
- More than exercise, diet and wealth, science has shown that sleep is the most important factor to our physical and mental wellbeing.
- In the first book of its kind written by a scientific expert, Professor Matthew Walker explores twenty years of cutting-edge sleep science.
- From what really happens during REM sleep to how caffeine and alcohol affect sleep and why our sleep patterns change as we grow older, Why We Sleep is the wake-up call we need: transforming our appreciation of the vital role of sleep in all aspects of our lives.
- Sleep Facts
- An afternoon nap increases the brain's learning capacity by 15-20%
- Sleep improves your memory, halting forgetting by 30-50%, relative to staying awake
- Not getting enough sleep increases sweet and salty cravings by 30-40%
- Sleep offers a three-fold boost in creativity and problem solving
- A good night's sleep improves time to physical exhaustion when exercising by 10-30%
Contents
- Part 1: This Thing Called Sleep
- To Sleep... – 3
- Caffeine, Jet Lag. and Melatonin: Losing and Gaining Control of Your Sleep Rhythm – 13
- Defining and Generating Sleep: Time Dilation and What We Learned from a Baby in 1952 – 38
- Ape Beds, Dinosaurs, and Napping with Half a Brain: Who Sleeps, How Do We Sleep, and How Much? – 56
- Changes in Sleep Across the Life Span – 78
- Part 2: Why Should You Sleep?
- Your Mother and Shakespeare Knew: The Benefits of Sleep for the Brain – 107
- Too Extreme for the Guinness Book of World Records: Sleep Deprivation and the Brain – 133
- Cancer. Heart Attacks, and a Shorter Life: Sleep Deprivation and the Body – 164
- Part 3: How and Why We Dream
- Routinely Psychotic: REM-Sleep Dreaming – 193
- Dreaming as Overnight Therapy – 206
- Dream Creativity and Dream Control – 219
- Part 4: From Sleeping Pills to Society Transformed
- Things That Go Bump in the Night: Sleep Disorders and Death Caused by No Sleep – 237
- iPads, Factory Whistles, and Nightcaps: What’s Stopping You from Sleeping? – 265
- Hurting and Helping Your Sleep: Pills vs. Therapy – 282
- Sleep and Society: What Medicine and Education Are: Doing Wrong: What Google and NASA Are Doing Right – 296
- A New Vision for Sleep in the Twenty-First Century – 324
Conclusion: To Sleep or Not to Sleep – 340
Appendix: Twelve Tips for Healthy Sleep – 341
Illustration Permissions – 343
Acknowledgments – 344
Extract 1 from Chapter 1 ("Why We Sleep")
- Sleep is infinitely more complex, profoundly more interesting, and alarmingly more health-relevant. We sleep for a rich litany of functions, plural — an abundant constellation of nighttime benefits that service both our brains and our bodies. There does not seem to be one major organ within the body, or process within the brain, that isn’t optimally enhanced by sleep (and detrimentally impaired when we don't get enough). That we receive such a bounty of health benefits each night should not be surprising. After all, we are awake for two-thirds of our lives, and we don't just achieve one useful thing during that stretch of time. We accomplish myriad undertakings that promote our own well-being and survival. Why, then, would we expect sleep — and the twenty-five to thirty years, on average, it takes from our lives — to offer one function only?
- Through an explosion of discoveries over the past twenty years, we have come to realize that evolution did not make a spectacular blunder in conceiving of sleep. Sleep dispenses a multitude of health-ensuring benefits, yours to pick up in repeat prescription every twenty-four hours, should you choose. (Many don’t.)
- Within the brain, sleep enriches a diversity of functions, including our ability to learn, memorize, and make logical decisions and choices. Benevolently servicing our psychological health, sleep recalibrates our emotional brain circuits, allowing us to navigate next-day social and psychological challenges with cool-headed composure. We are even beginning to understand the most impervious and controversial of all conscious experiences: the dream. Dreaming provides a unique suite of benefits to all species fortunate enough to experience it, humans included. Among these gifts are a consoling neurochemical bath that mollifies painful memories and a virtual reality space in which the brain melds past and present knowledge, inspiring creativity.
- Downstairs in the body, sleep restocks the armory of our immune system, helping fight malignancy, preventing infection, and warding off all manner of sickness. Sleep reforms the body’s metabolic state by fine-tuning the balance of insulin and circulating glucose. Sleep further regulates our appetite, helping control body weight through healthy food selection rather than rash impulsivity. Plentiful sleep maintains a flourishing microbiome within your gut from which we know so much of our nutritional health begins. Adequate sleep is intimately tied to the fitness of our cardiovascular system, lowering blood pressure while keeping our hearts in fine condition.
- A balanced diet and exercise are of vital importance, yes. But we now see sleep as the preeminent force in this health trinity. The physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise. It is difficult to imagine any other state — natural or medically manipulated — that affords a more powerful redressing of physical and mental health at every level of analysis.
- Based on a rich, new scientific understanding of sleep, we no longer have to ask what sleep is good for. Instead, we are now forced to wonder whether there are any biological functions that do not benefit by a good night’s sleep. So far, the results of thousands of studies insist that no, there aren’t.
- Emerging from this research renaissance is an unequivocal message: sleep is the single most effective thing we can do to reset our brain and body health each day — Mother Nature’s best effort yet at contra-death. Unfortunately, the real evidence that makes clear all of the dangers that befall individuals and societies when sleep becomes short have not been clearly telegraphed to the public. It is the most glaring omission in the contemporary health conversation. In response, this book is intended to serve as a scientifically accurate intervention addressing this unmet need, and what I hope is a fascinating journey of discoveries. It aims to revise our cultural appreciation of sleep, and reverse our neglect of it.
Plan of the Book (Extract 2 from Chapter 1 "Why We Sleep")
- Part 1 demystifies this beguiling thing called sleep: what it is, what it isn’t, who sleeps, how much they sleep, how human beings should sleep (but are not), and how sleep changes across your life span or that of your child, for better and for worse.
- Part 2 details the good, the bad, and the deathly of sleep and sleep loss. We will explore all of the astonishing benefits of sleep for brain and for body, affirming what a remarkable Swiss Army knife of health and wellness sleep truly is. Then we turn to how and why a lack of sufficient sleep leads to a quagmire of ill health, disease, and untimely death — a wakeup call to sleep if ever there was one.
- Part 3 offers safe passage from sleep to the fantastical world of dreams scientifically explained. From peering into the brains of dreaming individuals, and precisely how dreams inspire Nobel Prize-winning ideas that transform the world, to whether or not dream control really is possible, and if such a thing is even wise — all will be revealed.
- Part 4 seats us first at the bedside, explaining numerous sleep disorders, including insomnia. I will unpack the obvious and not-so- obvious reasons for why so many of us find it difficult to get a good night’s sleep, night after night. A frank discussion of sleeping pills then follows, based on scientific and clinical data rather than hear-say or branding messages. Details of new, safer, and more effective non-drug therapies for better sleep will then be advised. Transitioning from bedside up to the level of sleep in society, we will subsequently learn of the sobering impact that insufficient sleep has in education, in medicine and health care, and in business. The evidence shatters beliefs about the usefulness of long waking hours with little sleep in effectively, safely profitably, and ethically accomplishing the goals of each of these disciplines. Concluding the book with genuine optimistic hope, I lay out a road map of ideas that can reconnect humanity with the sleep it remains so bereft of — a new vision for sleep in the twenty-first century.
Conclusion: To Sleep or Not to Sleep (p. 340)
- Within the space of a mere hundred years, human beings have abandoned their biologically mandated need for adequate sleep — one that evolution spent 3,400,000 years perfecting in service of life-support functions. As a result, the decimation of sleep throughout industrialized nations is having a catastrophic impact on our health, our life expectancy, our safety, our productivity, and the education of our children.
- This silent sleep loss epidemic is the greatest public health challenge we face in the twenty-first century in developed nations. If we wish to avoid the suffocating noose of sleep neglect, the premature death it inflicts, and the sickening health it invites, a radical shift in our personal, cultural, professional, and societal appreciation of sleep must occur.
- I believe it is time for us to reclaim our right to a full night of sleep, without embarrassment or the damaging stigma of laziness. In doing so, we can be reunited with that most powerful elixir of wellness and vitality, dispensed through every conceivable biological pathway. Then we may remember what it feels like to be truly awake during the day, infused with the very deepest plenitude of being.
Twelve Tips for Healthy Sleep (pp. 341-2)
- These were taken from the NIH Medline Plus, National Library of Medicine (US) in 2012. A Long URL was given, so I Googled the latest version: MedlinePlus: Healthy Sleep.
- The points – with my comments as a footnote – are as below, though with less explanation than in the list cited in the book.
- Go to bed and wake up at the same time every day
- Avoid caffeine, especially in the afternoon and evening
- Avoid nicotine
- Exercise regularly, but don't exercise too late in the day
- Avoid alcoholic drinks before bed
- Avoid large meals and beverages late at night
- Don't take a nap after 3 p.m.
- Relax before bed, for example by taking a bath, reading or listening to relaxing music
- Keep the temperature in your bedroom cool
- Get rid of distractions such as noises, bright lights, and a TV or computer in the bedroom. Also, don't be tempted to go on your phone or tablet just before bed.
- Get enough sunlight exposure during the day
- Don't lie in bed awake; if you can't sleep for 20 minutes, get up and do something relaxing
- These 12 items don’t quite tie in with the list in the book, which combines the injunctions against caffeine and nicotine and the suggestions about bedroom temperature and distractions, though it splits out relaxation and hot baths. The missing item on Medline is the inculcation to avoid sleep-disrupting medication.
- Also, Medline encourages you to see your doctor if you have insomnia or sleep apnea – which our author would agree with – but supports the dispensation of over-the-counter sleep aids, which he wouldn’t!
- Comments: I follow most of these bits of advice, with the following exceptions:-
- I drink a lot of weak coffee all day, including before bed. I don’t find it has any impact on my falling asleep, which is usually pretty instantaneous.
- I usually have two sherry-glasses of wine before bed, as a relaxant. It works fine. It’s about ‘one drink’ by US reckoning.
- Sometimes rain and dog-walking duties mean I have to have my nap after 15:00, but since I don’t go to bed until circa 02:00 it makes no difference.
- Warm baths – you must be joking! But as I don’t have difficulty falling asleep when I stick to my usual schedule, it doesn’t matter.
Notes
- I’m willing to believe that sleep has the above multitudinous benefits. However, a question I have is whether the sleep has to be contiguous; in particular how it ties in with siestas, both Iberian and Chinese, with Carthusian ‘broken sleep’ and with the lifestyle recounted in "Everett (Daniel) - Don't Sleep There are Snakes: Life and Language in the Amazonian Jungle".
- I have six hours or so sleep overnight and one hour or so in the afternoon. If I don’t have my afternoon nap, I’m good for nothing for the rest of the day. That could be down purely to the brevity of the night’s sleep, but I don’t think so.
- Another issue is getting to sleep and staying asleep. I’m fortunate that – occasional exceptions aside (whether caused by worry, illness, external factors or schedule disruption) – I sleep very well. Off like a light with no need to get up in the night or have a drink, etc. I think this is down to my routine, non-standard though it may be. If I go to bed early ‘to have a good night’s sleep’ I can’t get to sleep for hours and hence feel worse the next day than if I’d gone to bed late.
- I should, though, have an extra half-hour overnight.
- The author is very critical of caffeine use. It seems that some people have a more efficient enzyme that removes caffeine from the system (it seems its half-life is usually 5 to 7 hours). I drink a lot of fairly weak coffee throughout most of the day and usually in the hours just before bed. Given that I have no trouble sleeping (in general), either I’m not as sensitive to caffeine as most people or my enzyme hoovers it up at lightning speed. Not the case with my wife, who tosses and turns all night if she has a tea or coffee any time after midday, or my elder daughter, who gets a migraine! Wikipedia: Caffeine looks interesting.
- p. 41 had an interesting contention about rats, maze-running, dreaming, and rate of neural firings. It was stated – doubtless correctly – that the same neural firings occur during the rats’ REM sleep as during the time they were learning to run the mazes, but that the memories were replayed more slowly (25-50% of the speed). OK, but it was suggested that this ‘explains’ why we have a ‘protracted experience of time during REM sleep’. This is the suggestion that if we’re dreaming, are woken by the alarm and press the ‘snooze’ button for 5 minutes, it ‘feels like’ we’ve been asleep for more than 5 minutes when we’re next rudely awakened. Even if this is true, I’d have thought that – if it takes longer for ‘things to happen’ in dreams – then time would appear to be compressed and therefore shorter. This could at least do with more explanation. Maybe the point is that when there’s less going on, time crawls by (because we’re bored), whereas when there’s lots going on ‘time flies by’. But I doubt this is the right model for experience of time’s passage in this context.
- … To be continued. Maybe.
In-Page Footnotes ("Walker (Matthew P.) - Why We Sleep: The New Science of Sleep and Dreams")
Footnote 1:
- According to Amazon! My edition just has brief plaudits!
Book Comment
Penguin; 1st edition (4 Jan. 2018)
Text Colour Conventions (see disclaimer)- Blue: Text by me; © Theo Todman, 2025
- Mauve: Text by correspondent(s) or other author(s); © the author(s)