Matthew P. Walker

Научпоп, компилирующий для обывателя последние достижения ученых, добрался и до жизненно важной и любимой нами сферы — сна. Профессор неврологии и психиатрии из Калифорнийского университета в Беркли смог донести новости науки в удобоваримой форме без формул и show more непонятных акронимов. Неудивительно, что книга стала бестселлером, тем более что вопрос крайне насущный.

Две трети взрослого населения всех развитых стран недосыпают, а последствия такого тотального недосыпа шокировали сначала ученых, а теперь, по прочтении, потревожат и вас. Всемирная организация здравоохранения вообще официально классифицировала работу в ночную смену как «вероятно канцерогенную». Без нормального сна все попытки сбросить вес тщетны — ни тренировки, ни диета не будут работать, более того, при коротком сне люди употребляют на 300 калорий больше, что в год легко дает 70 000 (с учетом выходных), а это в среднем +5 кг отнюдь не мышц. Тем, кто хвастает на работе, что им достаточно 4–5 часов сна, вы можете только посочувствовать. Это, вероятно, лишь совпадение, но и Рейгана, и Тэтчер, публично заявлявших такое, настиг Альцгеймер. Спать менее шести часов и быть годами работоспособными могут лишь люди с мутацией гена BHLHE41, а таких единицы. С другой стороны, теперь стало понятнее, как именно сон помогает мозгу учиться и закреплять навыки. Быстрый сон (со сновидениями) способствует креативности, демонстрируя смотрящему такие комбинации, которые бодрствующий мозг пресекает в зародыше. А зря, именно так появилась Yesterday «Битлз», а Отто Лёви придумал удостоенный Нобелевской премии эксперимент. Кстати, теперь с помощью сканера ученые могут понимать, что именно вы видите во сне, по крайней мере класс предметов.

Неожиданно, но сновидения, связанные с реально происходящими психологическими травмами — разводом, разрывом отношений, помогают перевернуть тяжелую страницу и войти в жизнь новых эмоций. Те же пациенты, в чьих снах не отражались мучительные переживания, не смогли отрешиться от печального события и оставались в депрессивном состоянии и год спустя. Бывает, что мы спим тревожно не из-за жизненных драм. Часто это происходит в первую ночь на новом месте. Как выяснилось, это разновидность однополушарного сна, существующего в полной мере у некоторых животных. Так, у нас одно полушарие мозга будет спать более чутко, выполняя сторожевую функцию, как, например, у птиц, сидящих в стае с краю. Качеству сна в книге вообще отведена отдельная часть. show less

Matthew Walker really, really thinks we all need some serious shut-eye, and he's not messing around when it comes to getting you on board – he hits you with both barrels on page one, and never lets up:

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 or not you will develop Alzheimer's disease. Inadequate sleep—even moderate reductions for just one show more 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 to cardiovascular disease, stroke, and congestive heart failure […] sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety, and suicidality.

And this is supposed to help me sleep better!? At least before, I just used to lie there going over the same three lines from ‘I Just Can't Wait to be King’; now, if I so much as drift into momentary consciousness at two a.m., I end up paralysed with alertness, calculating the gradually rising odds that my obese, cancer-ridden body will only cease to be a concern thanks to the merciful onset of my crippling dementia.

Eventually Walker just comes right out and admits that as far as the science is concerned, ‘wakefulness is low-level brain damage’, at which point you start to wonder how far he's really going to take this whole unconsciousness thing. But by then the damage is done. Your life is different. Come evening, when Hannah is pouring herself a glass of Sancerre and playing Gaga, I now appear in the doorway in my slippers, with a hot-water bottle clutched under one arm and a toothbrush jutting from my jaws. It may feel antisocial, but anything seems preferable to inviting the heart disease, obesity, cystitis, tennis elbow and plagues of locusts that Walker is otherwise promising.

A while back I got a Fitbit, which allows me to see in appalling detail just how much sleep I sometimes fail to get – the hypnograms, with their discrete stages of slumber, never quite stretching as far as you'd like them to. Thanks to this book, it's now possible to quantify exactly what I'm missing out on during such nights, as scientists have mapped more of the neurochemical processes involved than I ever realised: the deep, NREM sleep where memories are carefully transferred from short-term to long-term memory; then the ‘informational alchemy’ of REM-sleep dreaming, which sharpens creativity and conjures up solutions to our daytime problems.

The importance of sleep can be further appraised by its evolutionary heritage – it goes back about as far as life on earth. Walker finds that even ‘the very simplest form of unicellular organisms that survive for periods exceeding twenty-four hours, such as bacteria, have active and passive phases that correspond to the light-dark cycle of our planet’. Sleep is about the first thing natural selection locked in for us, and as far as we can tell every animal does it.

One always understood that sleep was a healthy thing, but somehow a full night of it is still often viewed as a luxury. On the evidence of this book, it's more like a medical necessity. Given working practices in many parts of the world, this is a big problem, and indeed part of Walker's mission is to explain that much of the developed world is suffering from a serious, chronic sleep deficit which is ultimately ‘a slow form of self-euthanasia’ – he is talking not just to individual sleepers, but to businesses and governments who have some responsibility to take what he says into account.

The difference between a four-star book and a five-star one is that while I might love both of them, I can keep a four-star book to myself, whereas a five-star book is one I can't shut up about to everyone around me. On that basis, despite its occasional infelicities, Why We Sleep makes the grade. It's passionate and clearly written, summarises a huge amount of research about which I knew little, and addresses a subject that obviously deserves the attention. It would take someone a lot more cynical than me to read this and not silently decide to make a few lifestyle changes – on which note, if you'll excuse me, I have some intensive, hi-octane pillow time to get to. show less

What an engaging exploration into the purpose of sleep! Nature wouldn’t waste an enormous proportion of humans’ (indeed, all creatures’) daily consciousness to sleep -- and in the process put them at enormous vulnerability to predation -- unless there was enormous benefit. This book goes broad and deep into those physical and psychological benefits and the corresponding risks (physical- and mental-health problems (including dementia) and early death) associated with not getting enough show more sleep. (And the author shows that we’re terrible judges of whether we’re getting enough.)

It’s written by a professor of neuroscience and psychology, so while some of the substantiation is biological, more of it is via behavioral and imaging studies. He notes the differing needs, timing and composition of sleep in infants, children, teens, adults and seniors. He describes the hormones/chemicals that promote wakefulness or sleep, including how we hinder their effects, and stresses that alcohol and sleep meds sedate the brain, which is not sleep. Among other physical aspects, sleep regulates immunity (including the destruction of early cancers and mounting an adequate response to immunization) and metabolism (including appetite and cardiovascular health).

But it is the psychological effects that fascinated me. Early in the sleep period (I’ll call it “night”), the sleep cycles are composed predominately of non-REM (NREM) sleep, while later in the night they reverse to predominately REM sleep. NREM sleep serves to move what’s learned/experienced during the day into long-term storage; REM sleep integrates that new material with everything that’s already there; and dreaming (during REM sleep) serves to de-escalate emotions and enable creativity (thus truth in the adages to “sleep on it” and that “things will look better in the morning”). A key factor is that the brain does this work each night for the prior waking period, and when it’s impaired by poor sleep or a short sleep, there’s really no make-up opportunity.

Life-changing for me and recommended for everyone. show less

If you're someone who doesn't sleep well, or who regularly sleeps less than 7 or 8 hours per night, I'm torn between screaming at you to read this book and telling you never to go near it, as it will absolutely scare the bejesus out of you (even if you imagine that you're a pretty good sleeper).

Matthew Walker (neuroscientist and sleep specialist) doesn't beat around the bush - sleep is VITALLY important to our health, and in an age when less and less sleep seems to be impressed upon us as show more the norm we're collectively screwed if we don't wake up and smell the coffee (or perhaps that should be stop waking up early and smelling the coffee to try and compensate for all the work we didn't allow our brain to do overnight).

There's loads of fascinating stuff in here about the important, differing roles deep sleep and REM sleep play in keeping us healthy. I think of it a bit like software patch upgrades; they're needed to keep everything refreshed and working in tiptop condition, and we can ignore doing the install for a while by depriving our bodies of the sleep they need, but eventually the programme's going to stop working properly.

A few things particularly stood out for me. The link between Alzheimer's and long-term sleep problems (older people in particular suffer from much shorter amounts of deep sleep), the huge impact that even losing an hour of sleep has on your cancer fighting cells and the clinical proof of the impact shortened sleep has on our cognitive abilities. Also, the fact that humans are designed to have 2 sleep cycles per day, something which has been eradicated from most of western society, with the exception of some parts of Greece and Spain, for example, where the practice siesta is still observed (and in those parts of Greece where an afternoon nap is the norm, the average lifespan is much longer than in the USA, for example).

Walker spells it out in no uncertain terms - if you know someone who prides themselves on 'only needing 4 or 5 hours sleep' they're completely deluding themselves; we ALL need 7-8 hours sleep nightly for critical reset programmes in our brain to run properly.

My main criticism of this book is that in places Walker gets a bit long-winded and doesn't necessarily need to get lost in so much detail for a popular science book, but overall it's a really important book and one we should all read if we value our health and longevity.

4 stars - fascinating and alarming essential reading. show less