I think that if you ask anyone who knows me in-person they will tell you that I'm an unusually emotionally intensive person. My writing is also usually very emotionally intense but it tend to go through getting feedback from like 20 people who tell me to remove all of the excessive language and to tone it down before publication, so it ends up sounding normal. Comment do not go through this kind of process.

Hi Natália,

I want to apologize for lack of proper engagement with the post and lack of replies to you as well as a high level of combativeness in the comments I did leave.

This stuff makes me anxious and I feel like I'm just unable to properly explain what makes me disagree so much with you. 

My best attempt is that my takes are some combination of:

1. Academic literature is a highly adversarial playing field and although it's very tempting for smart outsiders to think that they can just go on Google Scholar and figure out what's going on, I don't think this is possible for the vast majority of fields of science and this is certainly not possible for sleep literature. It seems that this surface-area survey is basically what you tried to do and my understanding is that you
   1. never studied biology or neuroscience with critical discussions with specialists in the field
   2. never discussed the papers in-depth with people in the field
   3. never tried to holistically assess the quality of the literature
   4. never studied the history of science in-depth and the dynamics of scientific progress in general
2. very deep skepticism of sleep literature and the knowledge of how entire fields of science can be led astray and become detached from reality with me becoming convinced that this is indeed what happened with sleep science, thus me being extremely selective with the kind of evidence I take seriously (I tried to explain this in https://guzey.com/theses-on-sleep/#our-priors-about-sleep-research-should-be-weak).
   1. Thus, I have absolutely no issue with me disagreeing with meta-analyses in the field. They very barely count as real evidence for me in fields like sleep science.
   2. The "successful replications" you appeal to similarly just don't count for me. I have a pretty simple model of how they happen: sleep scientists sit around and come up with an experiment to do. Then if the experiment shows something in line with "sleep good, no sleep bad" they publish it; otherwise they try to make it seems like it's "sleep good, no sleep bad" or just don't publish it.
      1. Why would I think that such a strange thing happens? Because I think that the field is dominated by people who have the view "sleep good, no sleep bad" and publishing anything else is way more difficult + people usually become sleep scientists because they think that sleep is very important.
         1. Mass preference falsification is real https://www.youtube.com/watch?v=PW2kxREtdCs, mistaken consensus is real.
3. personal experience (very deep conviction that brains are totally fucked up and try to trick us all the time while also being incredibly liable to both self- and external psyops e.g. https://guzey.com/personal/my-journal/, e.g. my video game addiction, e.g. me literally falling asleep when I become anxious or really bored, e.g. me sometimes sleeping 3 hours and feeling fine without any stimulants and sometimes sleeping 8 hours and feeling sleepy, me knowing how much the expectations affect the mental state and how the video game addiction can be literally get expunged from my brain and be brought down to 0 by saying a single sentence to my wife [it is "I will not play video games for {duration}"]; me personally literally jumping out of bed without an alarm after 3 hours of sleep if i'm allowed to play video games and at the same time ability to sleep 8-9 hours in most other cases)
   1. You called some of my explanations of self and external psyops "epicycles" (in particular, the picture with how lack of sleep per se doesn't actually lead to lack of productivity) but I'm very confident that brains do stuff like this to us all the fucking time (my one certainly does). Most people are just not very good at introspection and don't notice this.
   2. mass psychogenic illness is real https://en.wikipedia.org/wiki/Mass_psychogenic_illness
4. I think that the very fact that acute sleep deprivation sometimes increases energy and mood should make almost everyone almost completely re-evaluate everything they know or think about sleep because this should just not happen under the "sleep is restorative and is necessary for good functioning" paradigm. 
   1. (Sleep deprivation can certainly increase energy/decrease brain fog/etc. both on depressed non-bipolar people and bipolar people in general and it seems that people in general are affected (e.g. https://www.reddit.com/r/slatestarcodex/comments/9tpk94/writing_in_the_morning/?st=jozurz3y&sh=4c0150e1).)
   2. even if we only take people with bipolar disorder: how the hell can they go on so few number of hours a night with their brain being manic but not simply breaking down?
5. to continue the previous points. The evidence I take seriously is:
   1. trusted personal experience
      1. where the way "trusted" experience are chosen relies on lots of heuristics, background knowledge, intuition, etc. and for an outsider it might look like cherry-picking, "epicycles", etc. (this also applied to 5.2 and 5.3 below)
   2. trusted anecdotes
   3. trusted field observations
   4. n-of-1-proof-by-contradiction-style arguments
      1. e.g. "A single-point mutation can decrease the amount of required sleep by 2 hours, with no negative side-effects" and "A brain surgery can decrease the amount of sleep required by 3 hours, with no negative-side effects" from my theses are good examples of this. My take is that just these two examples invalidate large chunks of the sleep literature by showing that normal people can have something tweaked just a little bit, radically decrease the amount of required sleep but remain the same otherwise, which simply would not have been possible if these 2-3 hours of sleep they lost were essential for anything important.
      2. Similarly with anecdotes of people sleeping very little for days on end yet being very functional because they are very stressed out/caffeinated/etc. The brains just keep working! Here (https://www.youtube.com/watch?v=3xtwu0xOrls), for example, you can see a 2004 UK TV show in which volunteers slept an average of 1.5-2 hours a night for about a week competing for 100,000 pounds. Yes, they become pretty sleepy over time and the cognition of some of them becomes pretty fucked up. But then, many of them remain close to 100% functional even after many days of super severe sleep deprivation (they don't have bipolar or anything like this -- just normal people), as you can see from the later episodes. Again, this TV show from 2004 for me invalidates probably like 90% of published sleep literature because according to the sleep literature consensus people should become almost incapacitated under such conditions and yet they just don't when they are sufficiently motivated.
      3. Similarly with Walker. I believe that he's a charlatan. He doesn't know the most basic facts about sleep (as the single most outrageous example for me, in paragraph 2 of chapter 1 of his book he wrote "Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer."), if you watch his talks, it's very clear that he just has no ability to evaluate evidence critically or just doesn't care. The fact that a charlatan directs the Center for Human Sleep Science at UC Berkeley and that he gives premier talks to neuroscience conferences tells me that that the entire field is deeply deeply broken. This, even with n-of-1 simply should not happen and shows that there are no well-functioning error-correction mechanisms in the field.
6. Just to reiterate: I believe that the points 4, 5.4.1, and 5.4.2 invalidate large chunks of sleep literature and are simply not possible under the default "sufficient sleep is good and necessary for proper functioning for normal people on the scale of a few days to a week".
7. BDNF thing is, I think, much stronger than you appreciate because: sleep literature is SUPER pro sleep. For everything under the sun they try to show that sleep is good, no sleep bad. The very fact that there's an open debate with lots of papers showing that BDNF is increased when you are sleep deprived, tells me that there's something super interesting going on, as otherwise the entire literature would very quickly converge on "oh yeah, just like with everything else good under the soon, BDNF decreases with lack of sleep"

Coincidentally, I wrote this comment after less than 3 hours of sleep today (had 100 mg of caffeine 5 hours ago and another 100 mg of caffeine 3 hours ago).

Thanks for the taking the time to look into my essay.

Mendonça's claim 1: Guzey’s /r/BipolarReddit evidence is misleading

Here's what Mendonça writes in her first point that so conclusively demonstrates that the point I make is "misleading":

[Guzey's] evidence from bipolar disorder patients is not representative of what you see in the general population: both long and short sleep duration are associated with depression

The paper Mendonça cites looks at long-term long sleep and long-term short sleep, with their association with depression. My claim and my evidence (from bipolar people) are concerned with short-term long sleep and short-term short sleep. That is, Mendonça's paper is simply not overlapping with with what I write about or what the evidence she calls "misleading" is concerned about. It is further puzzling that in her refutation of my argument she:

1. completely ignores the relationship between sleep and mania (i.e. she ignores one half of my argument and only discusses the part about depression).
2. completely ignores the fact that in ~50% of ALL people with depression (not just bipolar), short-term short sleep relieves depression.

I am similarly puzzled by a later accusation:

Guzey claims that “most sleep research is extremely unreliable and we shouldn’t conclude much on the basis of it,” but there are problems with that. Firstly because he doesn’t seem to believe that about sleep research that favors his hypotheses. Guzey, after all, uses sleep research to show that Matthew Walker’s book is terrible and fraudulent. So it seems that he wants to trust sleep research when it says that sleep deprivation is not as bad as Walker shows, but doesn’t want to trust it when it says that sleep deprivation is not harmless.

I wrote that most sleep research is extremely unreliable. And indeed, this is what I believe and this is why I'm so selective with the kind of evidence I use, preferring to show my readers Reddit comments left by bipolar people, instead of meta-analyses, and why, when I do use meta-analyses, I use them very cautiously. For example, in the essay, I used a meta-analysis exactly once when I noted in a point I dedicated to a paper about a study of hunter-gatherers that "There’s no causal evidence that sleeping 7-9 hours is healthier than sleeping 6 hours or less. Correlational evidence [from a meta-analysis] suggests that people who sleep 4 hours have the same if not lower mortality as those who sleep 8 hours and that people who sleep 6-7 hours have the lowest mortality."

What Mendonça seems to miss more generally is that meta-analyses, which she is relying on heavily, do not reflect reality: they reflect the consensus of an academic field. And if the academic field is confused and the majority of the papers published in it are garbage, then meta-analyses are going to be confused garbage as well.

Mendonça's claim 2: Chronic sleep deprivation might be associated with *decreased* BDNF expression, as shown by Guzey’s own sources

I believe that it is similarly confused. I write about sleep deprivation causing increase in BDNF. What does Mendonça have that contradicts my writing, supposedly by papers I cited myself?

1:

Chronic sleep deprivation and insomnia can act as an external stressors and result in depression, characterized by hippocampal BDNF downregulation along with disrupted frontal cortical BDNF expression, as well as reduced levels and impaired diurnal alterations in serum BDNF expression.

This quote talks about depression (due to chronic sleep deprivation and stress) being characterized by BDNF downregulation. This is not about sleep deprivation per se because sleep deprivation does not necessarily lead to depression.

2:

significantly decreased serum BDNF levels compared with sleep-healthy controls (n=24; F(1)=5.017; P=0.03; Figure 1a). In addition, serum BDNF levels were significantly correlated with severity of insomnia in all paricipants (n=50; rp=−0.409; P=0.004; Figure 1). [...] We found subjective sleep impairment to be associated with lower serum BDNF levels, whereas reported good sleep was related to higher serum BDNF levels, as shown for those suffering from current insomnia compared with sleep-healthy subjects.

This quote talks about people with insomnia having decreased BDNF. People with insomnia have all kinds of health issues and are famous for underestimating how much they sleep (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277880/) and using them to argue about the relationship between sleep deprivation and BDNF is misleading.

I regret citing this paper in my essay but it's indicative of the overall depth of Mendonça's arguments: instead of noting that using insomniacs as evidence is simply inappropriate for the point I was making and writing that I'm using inappropriate evidence, she doesn't note any issues with it and simply notes that it contradicts my point.

3:

[O]ur findings are in line with the hypothesis of an increased stress vulnerability due to sleep loss which may lead to a decrease in BDNF. [...] While we report a reduction of BDNF levels linked to sleep disturbance reflecting chronic stress on the one side, we and others consistently showed that prolonged wakefulness caused by SD (partial or total), which can be considered as an acute stressor for the brain, leads to a rapid increase of BDNF

This quote again talks about stress due to sleep loss, not sleep loss per se and specifically notes "we and others consistently showed that prolonged wakefulness caused by SD (partial or total), which can be considered as an acute stressor for the brain, leads to a rapid increase of BDNF", so I'm very confused by Mendonça uses it to contradict me.

I don't have the ability to go through every claim in the post and show what exactly is wrong with them, but my read that the rest are similarly confused: they seem to be somewhat related to what I wrote but mostly misinterpreted with their misinterpretations being "refuted" or shown "misleading".

(I'll reply in more substance by the end of the week -- have a big deadline coming up this Thursday)

From skimming the post, three parts stand out to me

1. the fact that acute sleep deprivation relieves depression in ~50% of people with depression seems completely unaddressed and Natália's section about bipolar people seems to imply that this would not be happening. I specifically noted in this the section Natália addresses by writing:

Lack of sleep is such a potent trigger for mania that acute sleep deprivation is literally used to treat depression. Aside from ketamine, not sleeping for a night is the only medicine we have to quickly – literally overnight – and reliably (in ~50% of patients) improve mood in depressed patients

2.

One of Guzey’s theses is that “[o]ccasional acute sleep deprivation is good for health and promotes more efficient sleep.” His argument supporting that thesis is pretty much that, because some types of acute stress (such as exercising and fasting) are good, and acute sleep deprivation causes acute stress, then acute sleep deprivation is also good. (Yes, that does seem to actually be the entirety of his argument in that section. You can read it yourself.)

The obvious problem with that argument is that the set of things that cause acute bodily stress is much larger than the set of things that cause long-term benefits. Stubbing your toe, for example, causes acute bodily stress. Guzey’s argument works equally well for showing that occasional toe-stubbing is good for health as for showing that occasional acute sleep deprivation is.

As far as I know, there's no evidence that stubbing depressed people's toes relieves their depression in 50% of the cases, which combined with the relationship with mania in bipolar people, and the analogical reasoning to exercise and fasting leads me to believe that acute sleep deprivation is good.

3. Natália misquotes me at the end of the piece. I never wrote that 6 hours of sleep is optimal. I have no idea how many hours of sleep is optimal and I believe (please let me know if this is not the case) I never stated that a particular amount of sleep is optimal.

What I wrote in the appendix of the Why We Sleep piece Natália linked to was:  "people who have the lowest mortality actually sleep 6 hours a night". Earlier in that article (which, it is clear that Natália read carefully), I specifically wrote "we should almost never use [epidemiological evidence] to claim causality".

The fact that I spotted these three points after spending ~3 minutes skimming the post do not make me optimistic about the rest of the critique, but, as noted above, I will reply in more detail in a few days.

re: persuasive intent -- yes, of course I want to persuade people but I'm believe I'm being very clear about the fact that some sections are just analogies.

My strongest objection to your writing style is the accusation that sleep researchers in general are doing shoddy research and culpable for the equivalent of killing people. This is the point at which I would have stopped reading your article (and lowered my likelihood of reading other things you write in the future), if it weren't for the fact that Elizabeth was the one who curated the piece.

I believe this is a very strong misreading of what I wrote. I did write that sleep researchers in general are doing shoddy research (I'm pretty sure this is true). I never wrote that they are culpable for the equivalent of killing people.

Here's the paragraph this is referring to, I believe:

Why are people not all over this? Why is everyone in love with charlatans who say that sleeping 5 hours a night will double your risk of cancer, make you pre-diabetic, and cause Alzheimer’s, despite studies showing that people who sleep 5 hours have the same, if not lower, mortality than those who sleep 8 hours? Convincing a million 20-year-olds to sleep an unnecessary hour a day is equivalent, in terms of their hours of wakefulness, to killing 62,500 of them.

I thought specifically about how to phrase the last sentence in order for it to be only about facts rather than accusing anyone and the "convincing a million 20-years-olds" appears clearly to be just a thought experiment to me.

This I agree with. As I noted in another comment, Guzey's a lot of things right here, except that the tone and format of his post makes his argument feel hard to respect. It comes across as ranty, manic, highly motivated ("passionate"), the sort of style we now associate with Qanon. But this is LessWrong, and I think that here, at least, we should try to focus on substance over style.

Tbh I'm very confused about the issues you have with my tone. I very deliberately called the post "Theses" on sleep! And I believe I very explicitly wrote that these are my conclusions from my reading of the literature and in no way am trying to make people think that the analogies that I thought of that I find convincing should be convincing to other people. I simply put forward some theses with extremely variable level of evidence between them but for each of these it is the case that I personally am convinced that they are actually true.

Yep, if someone was majorly undersleeping for a few days, they are probably going to be more sleepy and make more mistakes of attention/find it more difficult to concentrate and absorb the kind of information that they would need a tutor to absorb!

As an experiment -- you can ask a couple of your students to take a coffee heading to you when they are underslept and see if they continue to make mistakes and learn poorly (in which case it's the lack of sleep per se likely causing problems) or not (in which case it's sleepiness)

Have you done an explicit calculation of your perceived increased risk in Alzheimer's and compared it to QALY (potentially) gained by decreasing amount of sleep?

Yep, I sometimes manage to ask my body to wake up at a certain time and it does it when there's something I care a ton about waking me up a few minutes before the alarm.