"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 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 toward cardiovascular disease, stroke, and congestive heart failure. Fitting Charlotte Brontë’s prophetic wisdom that “a ruffled mind makes a restless pillow,” sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety, and suicidality."
The book isn't so much about "why we sleep" but rather "why you should sleep more" – 350 pages of Walker telling you about study after study after study after study comparing well-slept to underslept people, and all of the afflictions the latter suffer from, often without even noticing it (and the consequences for industry and society).
While I found his contrived writing style annoying at times, the content is the kind of eye-opening that makes you want to buy a dozen copies just to give to your family and friends.
I think sleep deprivation can become addictive. Some people don't seem to get, or gets used to, the despair and come to enjoy the single minded numbness to the point where it is actually uncomfortable for them to sleep well and come out of 'survival mode'.
You can even kind-of emergency manage depression with timed sleep deprivation if there are huge reasons (e.g. pregnancy) you should be off your meds.
(In no way am I recommending this though)
But then, the elevated mood begets more sleep deprivation and soon you're euphoric, reckless and finally manic as hell.
In a way, bipolar mania is like being addicted to yourself.
That said, I think it is a very important book, and now I’ve hopefully resolved my sleep issue (with thanks to some of the comments on https://news.ycombinator.com/item?id=16671944 - primarily the advice about having a regular “sleep schedule”) I look forward to finishing it!
Don't be disingenuous.
Sounds like shaming to me.
In any case, I guess what I'm saying is you seem to have researched the topic and your spending an extra minute or two giving a few more details will probably save a bunch of other folks ten times that, in aggregate.