4 ms·

The majority of comments seem to have the belief that the need for 8 hours of sleep is truth, and seem to mostly be making up various excuses why the increase i

by Tenoke 6y ago

The majority of comments seem to have the belief that the need for 8 hours of sleep is truth, and seem to mostly be making up various excuses why the increase in sleep here doesn't show results. As far as I can tell, the 8 hours figure is on pretty shaky grounds and most believe it due to pop-science books like 'Why we sleep' and it could easily be the case that this is just another study showing how exaggerated that claim is.

bdibs 6y ago
Between 7 and 9 hours of sleep has been recommended from every sleep research group I can find, long before that book came out. Recent consensus statement: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546/
- Pyramus 6y ago
  This estimate is quite robust, e.g. researchers observed how long different hunter-gatherer societies sleep etc. In addition it should be note that it's distributed like a Gaussian distribution, so there will be plenty of people outside this range.
- Tenoke 6y ago
  Long before that specific book came out. If you look at how they arrived at the recommendation here, a lot of it was based on discussions and voting by 15 experts chosen by the US Department of Health. Actual studies are much less conclusive (see the one we are commenting on for example) and the evidence for 8 hours of sleep is shaky and the difference from 6 to 8 is rarely especially big even when it is supported with anything under 6 and over 8 having negative effect. Check this systematic review (first result of my search[0]) which seems extremely sympathetic to 8 hours, yet the actual results are: >compared with 7 h of sleep per day, a 1-h decrease in sleep duration was associated with 6% increased risk of all-cause mortality and a 1-h increase in sleep duration was associated with a 13% increased risk of all-cause mortality (N = 241 107 adults in 43 articles) So, going from 7 to 8 hours increases risk more than going from 7 to 6! Further >Itani et al. (2017) reported that short sleep duration (<6 or ≤7 h/day) was not significantly associated with the incidence of depression compared with normal sleep duration (N = 16 257 adults in 2 articles) >Lo et al. (2016) reported that extreme sleep durations (both short and long) were associated with cognitive decline compared with the reference sleep of 7 to 8 h/day (N = 97 264 adults in 18 articles) But again it's only at the extremes that there is decline, which seems to be more like 3+ hours less than 8 a day. >Health-related quality of life No systematic review was identified that examined the association between sleep duration and health-related quality of life. etc. If you go through actual studies and systematic reviews it is really hard to make much of a case that 6 hours is much worse (if at all) than 8, yet alone anything more than that. 0. https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0034 https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0034
  - Pyramus 6y ago
    This is one of my favourite topics that seems straightforward (What's the optimal sleep length?) but is a lot more tricky. > If you go through actual studies and systematic reviews it is really hard to make much of a case that 6 hours is much worse (if at all) than 8, yet alone anything more than that. The absence of evidence that 6 is much worse than 8 hours is not evidence that 6 is not much worse than 8 hours. It doesn't matter that much in this case because we already agree that it's worse - the question is how much worse. Better or worse is measured in averages, on a population level, and here we see exactly the adverse health outcomes you cited (and a lot more that you didn't cite) from [1]. Here is where things get tricky for two reasons: 1) Population studies don't translate into personal health advice - there are plenty of folks striving on 4 hours a night (but they are rare in relative terms). 2) Overly long sleep durations are also associated with adverse health outcomes, and we don't know why! We believe we have a good understanding why short sleep is linked to some health outcomes linked to certain metabolic pathways, e.g. obesity or diabetes. And also we can take one individual, restrict their sleep, and see that their cognitive performance is impaired, and from here, it is reasonable to assume we understand the link between short sleep and accidents and injuries. For the overly long sleep however, we have no idea (as far as I'm aware of).
    - Tenoke 6y ago
      >The absence of evidence that 6 is much worse than 8 hours is not evidence that 6 is not much worse than 8 hours. It's not absense of evidence as in hasn't been tested - they have been compared and it doesn't really come off as worse or at best only a little worse (and in some cases better than 8). >It doesn't matter that much in this case because we already agree that it's worse - the question is how much worse. Who is this 'we'? My whole point is that people have this assumption and keep looking for ways to justify it even when confronted with evidence that it might not be the case as in the study posted here or the systematic review I posted. >and here we see exactly the adverse health outcomes you cited (and a lot more that you didn't cite) from [1]. But we don't see that. What I cited was that the evidence doesn't even suggest worse outcomes at 6 vs 8 hours in the biggest analyses out there.
currymj 6y ago
I need probably 7.5-8 hours of sleep. I'm very confident about this. If I get only 5-6 hours sleep for a couple nights, I become quite cognitively impaired; if it goes on long enough there are serious emotional effects too. There are people who insist that actually, 5-6 hours is fine, and that I must be lying, lazy, or deluding myself. These people are trying to make me stupid and miserable. It's an issue that provokes a lot of strong emotions, especially on the side of people who feel pressured to sleep less than they need.
- Tenoke 6y ago
  >It's an issue that provokes a lot of strong emotions, especially on the side of people who feel pressured to sleep less than they need. Perhaps you feel like it is much worse for the side you perceive yourself to be on. I, and plenty of other people have had very negative experiences and sleep-related anxiety because of all the people insisting that getting less than 8 hours of sleep is bad for you on flimsy evidence.
  - currymj 6y ago
    I agree with your analysis above -- a lot of the causal claims trying to connect <8hrs sleep to bad health outcomes are pretty dubious. People shouldn't worry about their lifespan or dementia or whatever. "Why We Sleep" unfortunately seems to have serious flaws. However I really do maintain that the anti-sleep attitude is much more common. There is always huge pressure in schools, the workplace, social life to cut into sleep. I think the reason "Why We Sleep" became so popular without facing much scrutiny is because many people were facing these pressures and desperate for some countervailing authority to point to.
- shlep21 6y ago
  Surely you concede that, even if 5-6 hours is not enough for you, it might still be enough for them.

by Tenoke 6y ago

bdibs 6y ago

Between 7 and 9 hours of sleep has been recommended from every sleep research group I can find, long before that book came out. Recent consensus statement: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546/

Pyramus 6y ago
This estimate is quite robust, e.g. researchers observed how long different hunter-gatherer societies sleep etc. In addition it should be note that it's distributed like a Gaussian distribution, so there will be plenty of people outside this range.
Tenoke 6y ago
Long before that specific book came out. If you look at how they arrived at the recommendation here, a lot of it was based on discussions and voting by 15 experts chosen by the US Department of Health. Actual studies are much less conclusive (see the one we are commenting on for example) and the evidence for 8 hours of sleep is shaky and the difference from 6 to 8 is rarely especially big even when it is supported with anything under 6 and over 8 having negative effect. Check this systematic review (first result of my search[0]) which seems extremely sympathetic to 8 hours, yet the actual results are: >compared with 7 h of sleep per day, a 1-h decrease in sleep duration was associated with 6% increased risk of all-cause mortality and a 1-h increase in sleep duration was associated with a 13% increased risk of all-cause mortality (N = 241 107 adults in 43 articles) So, going from 7 to 8 hours increases risk more than going from 7 to 6! Further >Itani et al. (2017) reported that short sleep duration (<6 or ≤7 h/day) was not significantly associated with the incidence of depression compared with normal sleep duration (N = 16 257 adults in 2 articles) >Lo et al. (2016) reported that extreme sleep durations (both short and long) were associated with cognitive decline compared with the reference sleep of 7 to 8 h/day (N = 97 264 adults in 18 articles) But again it's only at the extremes that there is decline, which seems to be more like 3+ hours less than 8 a day. >Health-related quality of life No systematic review was identified that examined the association between sleep duration and health-related quality of life. etc. If you go through actual studies and systematic reviews it is really hard to make much of a case that 6 hours is much worse (if at all) than 8, yet alone anything more than that. 0. https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0034 https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0034
- Pyramus 6y ago
  This is one of my favourite topics that seems straightforward (What's the optimal sleep length?) but is a lot more tricky. > If you go through actual studies and systematic reviews it is really hard to make much of a case that 6 hours is much worse (if at all) than 8, yet alone anything more than that. The absence of evidence that 6 is much worse than 8 hours is not evidence that 6 is not much worse than 8 hours. It doesn't matter that much in this case because we already agree that it's worse - the question is how much worse. Better or worse is measured in averages, on a population level, and here we see exactly the adverse health outcomes you cited (and a lot more that you didn't cite) from [1]. Here is where things get tricky for two reasons: 1) Population studies don't translate into personal health advice - there are plenty of folks striving on 4 hours a night (but they are rare in relative terms). 2) Overly long sleep durations are also associated with adverse health outcomes, and we don't know why! We believe we have a good understanding why short sleep is linked to some health outcomes linked to certain metabolic pathways, e.g. obesity or diabetes. And also we can take one individual, restrict their sleep, and see that their cognitive performance is impaired, and from here, it is reasonable to assume we understand the link between short sleep and accidents and injuries. For the overly long sleep however, we have no idea (as far as I'm aware of).
  - Tenoke 6y ago
    >The absence of evidence that 6 is much worse than 8 hours is not evidence that 6 is not much worse than 8 hours. It's not absense of evidence as in hasn't been tested - they have been compared and it doesn't really come off as worse or at best only a little worse (and in some cases better than 8). >It doesn't matter that much in this case because we already agree that it's worse - the question is how much worse. Who is this 'we'? My whole point is that people have this assumption and keep looking for ways to justify it even when confronted with evidence that it might not be the case as in the study posted here or the systematic review I posted. >and here we see exactly the adverse health outcomes you cited (and a lot more that you didn't cite) from [1]. But we don't see that. What I cited was that the evidence doesn't even suggest worse outcomes at 6 vs 8 hours in the biggest analyses out there.

currymj 6y ago

I need probably 7.5-8 hours of sleep. I'm very confident about this. If I get only 5-6 hours sleep for a couple nights, I become quite cognitively impaired; if it goes on long enough there are serious emotional effects too. There are people who insist that actually, 5-6 hours is fine, and that I must be lying, lazy, or deluding myself. These people are trying to make me stupid and miserable. It's an issue that provokes a lot of strong emotions, especially on the side of people who feel pressured to sleep less than they need.

Tenoke 6y ago
>It's an issue that provokes a lot of strong emotions, especially on the side of people who feel pressured to sleep less than they need. Perhaps you feel like it is much worse for the side you perceive yourself to be on. I, and plenty of other people have had very negative experiences and sleep-related anxiety because of all the people insisting that getting less than 8 hours of sleep is bad for you on flimsy evidence.
- currymj 6y ago
  I agree with your analysis above -- a lot of the causal claims trying to connect <8hrs sleep to bad health outcomes are pretty dubious. People shouldn't worry about their lifespan or dementia or whatever. "Why We Sleep" unfortunately seems to have serious flaws. However I really do maintain that the anti-sleep attitude is much more common. There is always huge pressure in schools, the workplace, social life to cut into sleep. I think the reason "Why We Sleep" became so popular without facing much scrutiny is because many people were facing these pressures and desperate for some countervailing authority to point to.
shlep21 6y ago
Surely you concede that, even if 5-6 hours is not enough for you, it might still be enough for them.