I've seen this posted all over the internet to great acclaim, and honestly, it just feels feverish and desperate to me, grasping at tiny points as if they refute the central thesis.<p>For example, the point that you linked to says that the official recommendations on sleep are "7 to 9 hours", which Walker simplified to "an average of 8 hours". I don't see how this simplification is so bad. The point is that these numbers are all much higher than the 5-6 hours many people claim to subsist on. It doesn't even change the numbers that much: slightly more than half of people sleep less than 8 hours, and slightly less than half of people sleep less than 7 hours. This nitpick does not refute the central point that having 5-6 hours of sleep generally impairs you, it only takes aim at phrasing.<p>I find point #2 (of 5) in this article especially laughable. Here it's claimed that sleep deprivation is actually a good thing, because it can be used as a temporary treatment for severe depression. Under this logic, bulimia is a healthy habit because you should induce vomiting after being poisoned.
While I can't speak to the accuracy of the book criticized, science in general is riddled with similar problems. Follow the citation trail and you'll often find that a cited article doesn't say what was claimed or says something similar but not quite the same. Alternatively, you might see that the cited article does say what is claimed, but the evidence is weak.<p>When researchers talk about all of the "low hanging fruit" being taken, it seems to me that they're blind to all the nonsense that appears once you start following the citation trail. Maybe every topic has been <i>touched</i>, but even something that seems definitive in a review article could have major flaws when examined more closely.<p>I'm almost done a PhD in engineering, and this has been my experience at least. I try to "debunk" something in roughly half my publications now.<p>Edit: I don't mean to suggest that identifying many of these problems is <i>easy</i>, just that it's not done frequently enough. For example, if you're doing research in a particular field, you're probably basing it partly on previous review articles. Take a look at some primary sources in addition to that. This applies extra if you're <i>writing</i> a review article. Don't just mirror what some previous review articles say and cite some newer papers. Find some old but good papers that were missed by previous reviews. Check primary sources. Etc. This is the job of a someone writing a review in my view.
I got a strong motivated reasoning/bullshit vibe from Walker in this interview: <a href="https://www.npr.org/2018/07/20/630792401/sleep-scientist-warns-against-walking-through-life-in-an-underslept-state" rel="nofollow">https://www.npr.org/2018/07/20/630792401/sleep-scientist-war...</a><p>Particularly this section:<p>> “Sleep is not like the bank. So you can't accumulate debt and then try and pay it off at a later point in time. And the reason is this - we know that if I were to deprive you of sleep for an entire night - take away eight hours - and then in the subsequent nights, I give you all of the sleep that you want - however much you wish to consume - you never get back all that you lost. You will sleep longer, but you will never achieve that full eight-hour repayment as it were. So the brain has no capacity to get back that lost sleep...”<p>I don’t think this follows - seems likely to me that sleep is not some linear time thing and that there’s a standard overhead that doesn’t need to be repeated to extend and make up the time. This feels like a symptom of not understanding the mechanism and making a bad assumption.<p>I also found the “I won’t mention the cognitive failures I can detect” irritating. If there’s some actual thing to mention, say it - this kind of thing sets off alarms for me.<p>It doesn’t surprise me that the rest is similarly bad, I’m glad someone dug into it.
The author of "Why We Sleep" has written a blog post responding to the OP article and other questions from readers:<p><a href="https://sleepdiplomat.wordpress.com/2019/12/19/why-we-sleep-responses-to-questions-from-readers/" rel="nofollow">https://sleepdiplomat.wordpress.com/2019/12/19/why-we-sleep-...</a>
>I have many stories of people who slept well on less than eight hours of sleep, read Walker’s book, tried to get more sleep and this led to more time awake, frustration, worry, sleep-related anxiety, and insomnia.<p>This is me. I get at most 7 hours, usually 6. I only feel impaired if I drop down to 4.<p>Reading about Matthew Walker's research years ago caused much anxiety and a loss of sleep, how ironic.
Not sure why this links to section 5 but the entire page is worth reading. It a little ironic to say that this article changed my perspective on sleeping (considering this article is showing how you shouldn't believe the first thing you read) but given how little research I had done prior, I think I at least know now that there's a lot more that I don't know.