> This is built on the premise that the modern 8 hour night is settled science.
What do you mean by this? Urging people to sleep enough is not really a new and untested concept.
Is there a strong reason to think that frequently sleeping <8 hours is unlikely to cause harm? I think it would still be prudent to give all the studies in the article some consideration.
> “Sleeping 8.5 hr. might really be a little worse than sleeping 5 hr.”
How can people even take this kind of pseudo-science seriously?
If I sleep for 5 hrs, I'm a complete zombie during the day, unproductive and depressed.
If I sleep for 8.5 hrs (which is how long I sleep naturally), I feel great, productive, and happy. I get way more done.
There are all sorts of studies showing all the negative effects of not getting enough sleep -- that sleep-deprived doctors, for instance, are basically acting under an impairment equal to a few drinks of alcohol.
The idea that people in general are getting too much sleep is really quite preposterous.
> Also nice how they IMMEDIATELY ran into a continuing fraction 1/3, which is exactly the point of the 60-minute hour, 24-hour day, or 360-degree circle: lots of factors.
While I agree in principle, this example is not evidence of it. It's not like we measured the amount of sleep needed and it's precisely 8 hours. A more reasonable thing to say would be: You need to sleep for 3.5 metric hours.
> But really, 90% of the time I just have to sleep more.
I agree to this but I think the bigger problem is - How much more is actually "more"? Do you any literature about how to actually find your sleep length time?
>A professor I collaborate with at Penn State named Orfeu Buxton says that 8.5 hours of sleep is the new eight hours. In order to get a healthy eight hours of sleep, which is the amount that many people need, you need to be in bed for 8.5 hours.
So, the title is misleading. It means you should lie in bed for 8.5 hours in order to actually be asleep for 8 hours.
That said, this article has plenty of good insight and is well-written.
> The average length of nighttime sleep was around 6.5 hours in both groups, though no information was taken on the specific duration or timing of the naps taken
> What if it takes 19 minutes to fall asleep and then your alarm goes off after 1 minute of sleep?
That's a successful nap.
IME there's not much difference between 1 minute of sleep and 15 minutes. Both give me a similar recharge. I think a large part of it is relaxing enough to actually fall asleep.
> People who sleep 5 hours or less a night deprive their body of the opportunity to get enough deep sleep, which occurs near the beginning of the night.
I'd like that explained to me. If it's something that happens near the beginning of the night how does duration affect it?
This is very true for me, much to my surprise. I used to get by on 3 to 4 hours every night but that seems to have really caught up with me. If I don't get 8 hours minimum now I'm woozy the rest of the day.
> I've always wondered if we're going to one day find out that the 8 hours sleep thing was wrong and that it's physical exercise we truly need.
Two comments on that: The 8 hours sleep is a population average. It is very unlikely that you will need 8 hours of sleep, very likely your body will need more or less, and this will change as you age. You might very well be a 6 hours type.
That would basically invalidate what we know from animals - they are most vulnerable when they sleep, so it's unlikely evolution mad a mistake given all animals sleep, even the ones that don't have brains.
> There's no dispute there are deleterious effects of sleep deprivation and accruing sleep debt, and that people would be better off with a full 8 hours of sleep.
I question this, given that modern hunter gatherers only get about 6.5-7.0 (quality) hours of sleep.
Probably, most of us in the modern world have poor quality sleep, and this confounds epidemiological studies by creating the illusion that we need long duration of sleep.
There's also genetic variability in sleep duration needs. A small number of people are legitimately fine on 4-5 hours.
> also produce the same finding amongst people averaging over 9 hours a night.
Again, confounds. Depressed people, unemployed people, etc. The problems with empirical sleep research are largely methodological problems that all of epidemiology faces.
> I hit the REM sleep phase within a couple of minutes. Most people need 90 minutes to reach REM sleep. So that alone means 4h30m of my sleep is equivalent to 6 hours for a 'normal' person.
That would be true if REM sleep were the only sleep that counts, but light and deep NREM sleep has functions, too. Functions that REM sleep cannot perform.
>We know that, amongst other things, sleep is absolutely necessary to clear out toxins that build up in the brain during one's waking hours, and we know that people who get less than 7 hours of sleep per night are themselves at a significantly heightened risk of neurodegenerative diseases.
We know that? Because meta-analyses suggest that at even 6 hours you have less all-cause mortality than at 8 hours of sleep[0] and I'm yet to see systematic reviews/meta-analyses suggest that going under 7 hours is as bad as pop science claims.
0. https://guzey.com/files/books/why-we-sleep/shen2016.jpg from Shen X, Wu Y, Zhang D. Nighttime sleep duration, 24-hour sleep duration and risk of all-cause mortality among adults: a meta-analysis of prospective cohort studies. Scientific Reports. 2016 Feb 22;6:21480
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.
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