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Those in the study were low-income adults in Chennai, India who sleep only 5.5 hours per night on average despite spending 8 hours in bed. The key takeaway was

Those in the study were low-income adults in Chennai, India who sleep only 5.5 hours per night on average despite spending 8 hours in bed. The key takeaway was: > increased nighttime sleep had no detectable effects on cognition, productivity, decision-making, or well-being, and led to small decreases in labor supply. I find the result surprising. When I get under 6 hours I see a clear drop off in performance.

A4ET8a8uTh0 6y ago
Good grief. It almost makes me question what information is missing from the abstract since I don't know how one can consistently run on fumes without it affecting cognition, productivity or decision making.
- llarsson 6y ago
  The insane stress levels from being in their situation also affects cognition. So I am not surprised if merely looking at sleep amounts fails to explain differences.
  - lifeisstillgood 6y ago
    Highly likely this is a confounding factor - and compensating for it is essentially every decent policy for the last 50 years in the West.
    - lanstin 6y ago
      There is also a dynamic systems side to sleep rhythms. Quite likely there are stimuli you can randomly experience that shift your sleep cycle into a chaotic regime and then you need a good knock to the light and activity levels to reset to stability.
- throwawaysleep 6y ago
  Throwaway as I don't want to admit that I feel permanently cognitively impaired. Anecdotal, but I spent years not sleeping through university and sleeping in airports or on the train. Studied engineering and did a lot of hackathons and events and stuff. I figured out then that I didn't need full cognition or excellent decision making. I needed more hours cranking out work. I spent years sleeping just a few hours and often not sleeping on Saturday at all. I do a lot less of that now as work never has 2AM deadlines but it is as though I am permanently in that 80% functionality state. I never felt that I got out of that state. I have never regained my ability to be detail oriented. I am still reliant on the crutches of spell check and Grammarly and my IDE to make sure I don't do something stupid. I use task lists for every little thing in my day. So it is not that it does not impact cognition (at least in my case), it is that you get used to that impaired state and can't find a way back. Only a year and a half removed from that, so maybe it takes more time, but I still feel heavily optimized for output over quality, even though that is no longer needed. My baseline cognition was already impacted. More sleep just did not repair it.
  - sdenton4 6y ago
    Well, humans are also extremely error prone. Spell check, IDE helpers, delinters, automated testing, etc, all help check that things are correct automatically, which saves huge amounts of pain. I personally would always put more faith in someone who carefully checks their work than someone who thinks they don't need to. The second person is making mistakes and just doesn't realize it.
  - tartoran 6y ago
    But why are you doing this to yourself? The impact of not getting minimum sleep will have all sorts of bad effects on your body, not just cognition. Try to find a balance and what you consider as permanent cognitive impairment may revert, but even if it doesn’t you don’t want to make it worse
    - dijit 6y ago
      The parent is not continuing the practice, and has not for 18 months. It is noted in many sleep science studies that you cannot “recoup” lost sleep so this is plausible.
methyl 6y ago
> increased sleep duration by 27 minutes per night by inducing more time in bed Maybe 27 minutes is just not enough? I’m sure the results would be different if they started to get 7 hours instead of 5.5.
- Izkata 6y ago
  Possible "misaligned" is a better descriptor? I don't know about most people, but according to a sleep app I've been using for a while now, my REM cycles seem to be around 1.5-2 hours. Waking up at between cycles works well, adding a half hour does not.
- hawos 6y ago
  My thoughts as well. They still got less than 6 hours a night, and were already in a state of constant sleep deprivation.
- larsrc 6y ago
  +1. Though remember we're talking averages, and different people have different sleep needs. One would think some of them saw enough increase in sleep quality to show up in the stats.
Scoundreller 6y ago
The sentence before that is: "Contrary to expert predictions and a large body of sleep research". Was this study better science that disproved the existing body? Or poorer science? Or is there something problematic about sleep in Chennai? Or special about the people in Chennai? The full paper states: > An enormous body of research, mostly conducted in sleep labs in rich countries, documents severe negative impacts of sleep deprivation on a range of outcomes from attention and memory to mood and health (Lim and Dinges, 2010; Banks and Dinges, 2007). > While experimental evidence on the impact of increasing sleep in field settings is scarce, there is a widely-held belief among researchers and the public that reducing sleep deprivation would lead to improvements in economic outcomes (Walker, 2017). > To document these priors, we surveyed 119 experts from sleep science and economics who predicted sizable economic benefits, including a 7% increase in work output, of increasing sleep by half an hour per night from the low levels observed in our setting. Social science is fun.
- buu700 6y ago
  It could also be a function of their jobs, which weren't specified in the abstract. While insufficient sleep might cause physical discomfort and contribute to long-term health problems, if their job weren't highly physically or mentally demanding, I suspect that most people could get through the day with negligible detriment to their short-term economic output after having a cup of coffee.
  - eurasiantiger 6y ago
    The same can be said for other drugs that raise monoamine neurotransmitter levels, such as amphetamines.
    - lifeisstillgood 6y ago
      I doubt that a study 'Economic Benefits of Meth use on the Urban Poor' would be looked upon so well by the Ethics Board.
      - 6y ago
ArkanExplorer 6y ago
The study also needs to examine: - Noise pollution - Air pollution and ventilation (PM2.5 and CO2) - Bed comfort - Temperature and humidity Its possible that the home environment is so bad, that any increase in sleep yields no improvement. By contrast the workplace might be comparatively better controlled. Getting rid of fossil-fueled cooking, power generation and transport solves some of these issues.
- vinay_ys 6y ago
  A lot of homes in crowded cities like Chennai and Bangalore are tightly packed, congested and poorly ventilated. Air (dust) and noise (human activity) pollution is very high. Within the same congested dwelling, there maybe people who have to get up very early and go to work or come home late and sleep late which disrupts everyone's sleep. So it is highly likely that there is only 4-5 hour window at night when things are quiet enough to get good sleep.
jonplackett 6y ago
I read it as then saying they just got them to spend even more time in bed, despite the problem being they already have a lot of non-sleep time in bed. So it just reduced their time available to do other stuff. Am I misunderstanding?
- andi999 6y ago
  I read the abstract like the managed through information to reduce the non sleeping time in bed. They shd have used a fitness tracker to confirm, relying on the answers of people who might think their income depends on giving the 'right' answers is dangerous.
  - jonplackett 6y ago
    > increased sleep duration by 27 minutes per night by inducing more time in bed
    - andi999 6y ago
      From the article or abstract?
      - jonplackett 6y ago
        That was just in the abstract, what you see on the first page clicking the link.
        andi999 6y ago
        oh yes, thanks. I didnt parse the second half of the sentence. This totally doesnt make sense. I mean people seem to have a lot of interrupted sleep, wouldnt reduce the interruption increase sleep quality (and time)? (But probably due to small infants, so might be difficult to change that)
teachingassist 6y ago
> increased nighttime sleep... led to small decreases in labor supply. This indicates to me that they found something better to do, than this study.
gnopgnip 6y ago
What does spending 8 hours in bed but only sleeping for 5.5 hours mean specifically, and how is this measured? What is the expected amount of sleep for a healthy person that spends 8 hours in bed?
- lelanthran 6y ago
  > What does spending 8 hours in bed but only sleeping for 5.5 hours mean specifically It means that the TV is in the bedroom.
  - wccrawford 6y ago
    I'm not in India, and it's pretty common for me and my wife to spend time in bed that we're not sleeping, and I'm not talking about sex. I'm talking reading, browsing our phones, etc. We don't have a TV in there, but it's not a far stretch as I did when I was a kid, and so did my parents.
  - noisy_boy 6y ago
    Not sure why you are downvoted but this is pretty common in India and could be a contributing factor.
- larsrc 6y ago
  For a healthy person in a good bed without interruptions, 8 hours. But if you have trouble falling back to sleep after being woken up, you can lose a fair amount in a noisy environment. If your bed is bad, you may wake up or not fall into a deep sleep. And there are medical conditions that can make you be unconscious but not actually sleeping. Plus, high stress levels interferes with sleep.
deleted 6y ago
[deleted]
bjornsing 6y ago
Is it so surprising? The key takeaway could be rephrased “Healthy humans living under conditions similar to our evolutionary past naturally sleep an optimal amount of time at night.” > When I get under 6 hours I see a clear drop off in performance. Or is it “When I temporarily find myself in an environment with stress-levels similar to those of the people in the study I a) start to perform like them on modern day tasks and b) start to sleep like them.”?
rattray 6y ago
They were only able to induce a 27 minute increase, so still no more than 6 hours of sleep total.
matwood 6y ago
> When I get under 6 hours I see a clear drop off in performance. Same. I have a hard line at 6 hours. Over 6 and I'm good, less than 6 and I'm dead all day. I don't use an alarm and wake up naturally after around 7 hours of sleep, but that last hour I'm normally aware of the lighter sleep stage I'm in.
dukeofdoom 6y ago
Having stayed in an Indian city. Traffic noise and pollution is horrendous. I can see how these two factors would mess with sleep quality and duration.
pumaontheprowl 6y ago
I would look at the eight hours in bed as a possible explanation. While they weren't technically asleep, they likely still saw resting benefits just from laying down for a prolonged period of time.
__te__ 6y ago
> ... only 5.5 hours per night ... > ... increased sleep duration by 27 minutes per night ... I'm not surprised. On average, they were still under 6 hours, if barely. And if the sleep problems are interrupt-driven, this study does not appear to account for sleep quality.
- 88840-8855 6y ago
  Ok, then we could assume the hypothesis: Either you sleep 8 hours and are productive or you go down to 5.5 because 6 wont increase your efficiency levels either.
AndrewKemendo 6y ago
That wasn't the entire result. What I took away was this: >In contrast, short afternoon naps at the workplace improved an overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time.
abandonliberty 6y ago
The better takeaway is that napping is awesome! Moving work time into nap time resulted in a net productivity increase! That's amazing. If you consider taking 30 minutes of a 6 hour shift to nap, that means they have to be 10% more productive for the 5.5 hours after the nap. I'd suspect hawthorne here, even though it didn't show up in the night treatment group, but it would be interesting to see if this productivity increase is sustained in the long run. >In contrast, short afternoon naps at the workplace improved an overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time. Time spent napping >> time in bed. They're sufficiently exhausted by mid-day to get higher quality rest than they would by spending the same time in bed. If you're tired, you're better off getting up at your normal wake time, then taking a nap later.
GIFtheory 6y ago
They increased the participants sleep from 5.5 hours to 6 hours per night and expected improvements in cognition. This is not how sleep works, AIUI. This is like expecting to get rich after overdrawing your bank account by $140 per week instead of $175 per week.

A4ET8a8uTh0 6y ago

Good grief. It almost makes me question what information is missing from the abstract since I don't know how one can consistently run on fumes without it affecting cognition, productivity or decision making.

llarsson 6y ago
The insane stress levels from being in their situation also affects cognition. So I am not surprised if merely looking at sleep amounts fails to explain differences.
- lifeisstillgood 6y ago
  Highly likely this is a confounding factor - and compensating for it is essentially every decent policy for the last 50 years in the West.
  - lanstin 6y ago
    There is also a dynamic systems side to sleep rhythms. Quite likely there are stimuli you can randomly experience that shift your sleep cycle into a chaotic regime and then you need a good knock to the light and activity levels to reset to stability.
throwawaysleep 6y ago
Throwaway as I don't want to admit that I feel permanently cognitively impaired. Anecdotal, but I spent years not sleeping through university and sleeping in airports or on the train. Studied engineering and did a lot of hackathons and events and stuff. I figured out then that I didn't need full cognition or excellent decision making. I needed more hours cranking out work. I spent years sleeping just a few hours and often not sleeping on Saturday at all. I do a lot less of that now as work never has 2AM deadlines but it is as though I am permanently in that 80% functionality state. I never felt that I got out of that state. I have never regained my ability to be detail oriented. I am still reliant on the crutches of spell check and Grammarly and my IDE to make sure I don't do something stupid. I use task lists for every little thing in my day. So it is not that it does not impact cognition (at least in my case), it is that you get used to that impaired state and can't find a way back. Only a year and a half removed from that, so maybe it takes more time, but I still feel heavily optimized for output over quality, even though that is no longer needed. My baseline cognition was already impacted. More sleep just did not repair it.
- sdenton4 6y ago
  Well, humans are also extremely error prone. Spell check, IDE helpers, delinters, automated testing, etc, all help check that things are correct automatically, which saves huge amounts of pain. I personally would always put more faith in someone who carefully checks their work than someone who thinks they don't need to. The second person is making mistakes and just doesn't realize it.
- tartoran 6y ago
  But why are you doing this to yourself? The impact of not getting minimum sleep will have all sorts of bad effects on your body, not just cognition. Try to find a balance and what you consider as permanent cognitive impairment may revert, but even if it doesn’t you don’t want to make it worse
  - dijit 6y ago
    The parent is not continuing the practice, and has not for 18 months. It is noted in many sleep science studies that you cannot “recoup” lost sleep so this is plausible.

methyl 6y ago

> increased sleep duration by 27 minutes per night by inducing more time in bed Maybe 27 minutes is just not enough? I’m sure the results would be different if they started to get 7 hours instead of 5.5.

Izkata 6y ago
Possible "misaligned" is a better descriptor? I don't know about most people, but according to a sleep app I've been using for a while now, my REM cycles seem to be around 1.5-2 hours. Waking up at between cycles works well, adding a half hour does not.
hawos 6y ago
My thoughts as well. They still got less than 6 hours a night, and were already in a state of constant sleep deprivation.
larsrc 6y ago
+1. Though remember we're talking averages, and different people have different sleep needs. One would think some of them saw enough increase in sleep quality to show up in the stats.

Scoundreller 6y ago

The sentence before that is: "Contrary to expert predictions and a large body of sleep research". Was this study better science that disproved the existing body? Or poorer science? Or is there something problematic about sleep in Chennai? Or special about the people in Chennai? The full paper states: > An enormous body of research, mostly conducted in sleep labs in rich countries, documents severe negative impacts of sleep deprivation on a range of outcomes from attention and memory to mood and health (Lim and Dinges, 2010; Banks and Dinges, 2007). > While experimental evidence on the impact of increasing sleep in field settings is scarce, there is a widely-held belief among researchers and the public that reducing sleep deprivation would lead to improvements in economic outcomes (Walker, 2017). > To document these priors, we surveyed 119 experts from sleep science and economics who predicted sizable economic benefits, including a 7% increase in work output, of increasing sleep by half an hour per night from the low levels observed in our setting. Social science is fun.

buu700 6y ago
It could also be a function of their jobs, which weren't specified in the abstract. While insufficient sleep might cause physical discomfort and contribute to long-term health problems, if their job weren't highly physically or mentally demanding, I suspect that most people could get through the day with negligible detriment to their short-term economic output after having a cup of coffee.
- eurasiantiger 6y ago
  The same can be said for other drugs that raise monoamine neurotransmitter levels, such as amphetamines.
  - lifeisstillgood 6y ago
    I doubt that a study 'Economic Benefits of Meth use on the Urban Poor' would be looked upon so well by the Ethics Board.
    - 6y ago

ArkanExplorer 6y ago

The study also needs to examine: - Noise pollution - Air pollution and ventilation (PM2.5 and CO2) - Bed comfort - Temperature and humidity Its possible that the home environment is so bad, that any increase in sleep yields no improvement. By contrast the workplace might be comparatively better controlled. Getting rid of fossil-fueled cooking, power generation and transport solves some of these issues.

vinay_ys 6y ago
A lot of homes in crowded cities like Chennai and Bangalore are tightly packed, congested and poorly ventilated. Air (dust) and noise (human activity) pollution is very high. Within the same congested dwelling, there maybe people who have to get up very early and go to work or come home late and sleep late which disrupts everyone's sleep. So it is highly likely that there is only 4-5 hour window at night when things are quiet enough to get good sleep.

jonplackett 6y ago

I read it as then saying they just got them to spend even more time in bed, despite the problem being they already have a lot of non-sleep time in bed. So it just reduced their time available to do other stuff. Am I misunderstanding?

andi999 6y ago
I read the abstract like the managed through information to reduce the non sleeping time in bed. They shd have used a fitness tracker to confirm, relying on the answers of people who might think their income depends on giving the 'right' answers is dangerous.
- jonplackett 6y ago
  > increased sleep duration by 27 minutes per night by inducing more time in bed
  - andi999 6y ago
    From the article or abstract?
    - jonplackett 6y ago
      That was just in the abstract, what you see on the first page clicking the link.
      - andi999 6y ago
        oh yes, thanks. I didnt parse the second half of the sentence. This totally doesnt make sense. I mean people seem to have a lot of interrupted sleep, wouldnt reduce the interruption increase sleep quality (and time)? (But probably due to small infants, so might be difficult to change that)

teachingassist 6y ago

> increased nighttime sleep... led to small decreases in labor supply. This indicates to me that they found something better to do, than this study.

gnopgnip 6y ago

What does spending 8 hours in bed but only sleeping for 5.5 hours mean specifically, and how is this measured? What is the expected amount of sleep for a healthy person that spends 8 hours in bed?

lelanthran 6y ago
> What does spending 8 hours in bed but only sleeping for 5.5 hours mean specifically It means that the TV is in the bedroom.
- wccrawford 6y ago
  I'm not in India, and it's pretty common for me and my wife to spend time in bed that we're not sleeping, and I'm not talking about sex. I'm talking reading, browsing our phones, etc. We don't have a TV in there, but it's not a far stretch as I did when I was a kid, and so did my parents.
- noisy_boy 6y ago
  Not sure why you are downvoted but this is pretty common in India and could be a contributing factor.
larsrc 6y ago
For a healthy person in a good bed without interruptions, 8 hours. But if you have trouble falling back to sleep after being woken up, you can lose a fair amount in a noisy environment. If your bed is bad, you may wake up or not fall into a deep sleep. And there are medical conditions that can make you be unconscious but not actually sleeping. Plus, high stress levels interferes with sleep.

deleted 6y ago

[deleted]

bjornsing 6y ago

Is it so surprising? The key takeaway could be rephrased “Healthy humans living under conditions similar to our evolutionary past naturally sleep an optimal amount of time at night.” > When I get under 6 hours I see a clear drop off in performance. Or is it “When I temporarily find myself in an environment with stress-levels similar to those of the people in the study I a) start to perform like them on modern day tasks and b) start to sleep like them.”?

rattray 6y ago

They were only able to induce a 27 minute increase, so still no more than 6 hours of sleep total.

matwood 6y ago

> When I get under 6 hours I see a clear drop off in performance. Same. I have a hard line at 6 hours. Over 6 and I'm good, less than 6 and I'm dead all day. I don't use an alarm and wake up naturally after around 7 hours of sleep, but that last hour I'm normally aware of the lighter sleep stage I'm in.

dukeofdoom 6y ago

Having stayed in an Indian city. Traffic noise and pollution is horrendous. I can see how these two factors would mess with sleep quality and duration.

pumaontheprowl 6y ago

I would look at the eight hours in bed as a possible explanation. While they weren't technically asleep, they likely still saw resting benefits just from laying down for a prolonged period of time.

__te__ 6y ago

> ... only 5.5 hours per night ... > ... increased sleep duration by 27 minutes per night ... I'm not surprised. On average, they were still under 6 hours, if barely. And if the sleep problems are interrupt-driven, this study does not appear to account for sleep quality.

88840-8855 6y ago
Ok, then we could assume the hypothesis: Either you sleep 8 hours and are productive or you go down to 5.5 because 6 wont increase your efficiency levels either.

AndrewKemendo 6y ago

That wasn't the entire result. What I took away was this: >In contrast, short afternoon naps at the workplace improved an overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time.

abandonliberty 6y ago

The better takeaway is that napping is awesome! Moving work time into nap time resulted in a net productivity increase! That's amazing. If you consider taking 30 minutes of a 6 hour shift to nap, that means they have to be 10% more productive for the 5.5 hours after the nap. I'd suspect hawthorne here, even though it didn't show up in the night treatment group, but it would be interesting to see if this productivity increase is sustained in the long run. >In contrast, short afternoon naps at the workplace improved an overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time. Time spent napping >> time in bed. They're sufficiently exhausted by mid-day to get higher quality rest than they would by spending the same time in bed. If you're tired, you're better off getting up at your normal wake time, then taking a nap later.

GIFtheory 6y ago

They increased the participants sleep from 5.5 hours to 6 hours per night and expected improvements in cognition. This is not how sleep works, AIUI. This is like expecting to get rich after overdrawing your bank account by $140 per week instead of $175 per week.