Any book of Why We Sleep’s length is bound to contain some factual errors. Therefore, to avoid potential concerns about cherry-picking the few inaccuracies scattered throughout, in this essay, I’m going to highlight the five most egregious scientific and factual errors Walker makes in Chapter 1 of the book. This chapter contains 10 pages and constitutes less than 4% of the book by the total word count.
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No, two-thirds of adults in developed nations do not fail to obtain the recommended amount of sleep
Suppose that you recommend that adults sleep 7-9 hours per night.
then, someone learns (a) that roughly 40% of people sleep less than 7 hours, roughly 25% sleep 7 hours, and roughly 35% sleep 8 hours or more, meaning that a bit over one-third of people sleep less than you recommend Linked data is for the US but it appears (a) that other developed countries have very similar sleep habits.
then they look at your recommendation and say that you recommended an average of 8 hours of sleep per night.
then they say that you recommended 8 hours of sleep per night
then they say that two-thirds of people sleep less than the 8 hours you recommended
Would this be a fair representation of your position and of the data or would this be misleading?
This is literally what Walker does in his book. On page 3, in the very first paragraph of Chapter 1, Walker writes:
Two-thirds of adults throughout all developed nations fail to obtain the recommended eight hours of nightly sleep.
In the footnote to this sentence he writes:
The World Health Organization and the National Sleep Foundation both stipulate an average of eight hours of sleep per night for adults.
Adults (26-64): Sleep range did not change and remains 7-9 hours
Here are the World Health Organization’s sleep recommendations:
The quote is empty because the WHO does not stipulate how much an adult should sleep anywhere. I don’t know where Walker got this information.
The rest of the post is written in a similarly exasperated and exhaustive nature, patiently taking down Walker’s unfounded claims page by page. (Again, all of this is just in Chapter 1).
While I have not individually vetted the claims in Guzey’s blog post, on face value it seems reasonably well-researched and careful, certainly more so than the book it was critiquing. There are alsofollowups on the StatModelling blog by Andrew Gelman, a famous Bayesian statistician and blogger.
Note that Guzey’s critique and the followups on Gelman’s blog came out after this forum post and most of the associated comments were published, and it will be somewhat unfair to blame commentators for not being aware of the scientific and factual errors of an acclaimed/professed “sleep scientist.”
Some people in the comments were recommending Why We Sleep. People may be interested in this update by Alexey Guzey:
Matthew Walker’s “Why We Sleep” Is Riddled with Scientific and Factual Errors
Here’s an excerpt:
The rest of the post is written in a similarly exasperated and exhaustive nature, patiently taking down Walker’s unfounded claims page by page. (Again, all of this is just in Chapter 1).
While I have not individually vetted the claims in Guzey’s blog post, on face value it seems reasonably well-researched and careful, certainly more so than the book it was critiquing. There are also followups on the StatModelling blog by Andrew Gelman, a famous Bayesian statistician and blogger.
Note that Guzey’s critique and the followups on Gelman’s blog came out after this forum post and most of the associated comments were published, and it will be somewhat unfair to blame commentators for not being aware of the scientific and factual errors of an acclaimed/professed “sleep scientist.”