Audiobook Review / Why We Sleep: The New Science of Sleep and Dreams


OK. Humans are prone to confirmation bias, where we like to search for things that support our own opinions. This book isn’t that – it’s pure confirmation.

Not sure about you but I have always loved sleep. Not a fan of having to go to bed (night owl), and certainly not a fan of waking up (again, night owl), but sleeping, yarp.


Apparently the evolutionary likelihood is because early birds did the early morning tribal protection from approx 6am, and night owls did the late, until approx 2am, and therefore, there was only a four hour gap where the tribe was in danger. It would be interesting to see whether there are any modern examples of this actually being the case in isolated tribes, as he doesn’t go into much detail regarding case studies outside of biology. Biologically, however, I am a more active person later in the day, and have always been. I know well my circadian rhythm is not in check with the modern 9-5 system. Mostly because I hate it and I treasure lie-ins, but also as I’m incredibly active later at night than is expected. I imagine a lot of people who read this book also had that eureka moment.

But this isn’t just an enforcement of why we sleep, or why we should get more, it is a fantastic resource of lengthy, long-term research into why sleep is so important, what can go wrong in our bodies if we don’t get enough of it, but also, what can go right.

Walker covers everything from the sleeping if babies in the womb, and the problems that occur from mothers drinking alcohol during pregnancy, to the benefits of correcting sleep issues for PTSD patients, to the process of learning, recall and enforcement of skills through getting better sleep.

He tells us of the life-shortening dangers of having less than (at least) 8-hours sleep time, the learning deficit cause by alcohol and its disruption of both n-rem and rem sleep, and the disruption to the natural (and distinct) circadian rhythm of teenagers by forcing them to go to bed early and get up early.

I, particularly, feel for that section the book. I was always a bad sleeper during my teenage and early adult years (not much has changed, but a little amazingly enough, explained this book), and now I know why. Not only is my circadian rhythm of the night owl variety (which is an evidence-based real thing now, not just a cover for people to call us lazy), but I have always worked better at night. The school system, as noted by Dr Walker, is not created for us, and therefore we are being shunted into an early bird’s rhythm, and losing our life cycle with it. Sound scary? Well it should be. Walker can give you definitive evidence that sleep deprivation can kill. Lots over a short period will kill quickly. A smaller amount over a longer period will kill slower, but kill it will.

And, the dreaded blue-light. Apparently an offshoot of our sea-dwelling ancestors, the blue-light reflection (if I recall) is what used to control the circadian rhythm of sea-dwellers, and so blue light now (evil LED) prevents sleep-drug melatonin from increasing in our brains (which sends us into sleepy mode) and keeps us awake instead. The evidence suggests that blue-light reduces melatonin production by 50%. FIFTY. And it takes around 3-hours after turning off a blue-light to get to the right levels of sleep melatonin.

Get a blue light filter on your tech, people.

I could write all day about this book, but I think the only thing that needs saying is for your own life benefit, spare 12 hours of it either listening to or reading this book. It could save your life, eh?