The best explanation I've heard for the three states of consciousness (NREM, REM and wakefulness), and one that the evidence in this article seems to support, is the default theory of sleep. This theory states (counterintuitively) that NREM is the default state of consciousness. However, for whatever reason an animal can't remain in NREM sleep forever (in humans, only 3-4 hours a day), so at that time it will switch to REM sleep. When it has some need (hunger, thirst, sex), it will wake up. When that need is satisfied, it returns to either NREM sleep or, failing that, REM sleep. REM sleep acts as a "holding state" that conserves energy and keeps the animal out of trouble.
I'm not sure if it's the accepted theory for sleep. I couldn't find references to it by name in journal articles, but perhaps it has another name. I learnt it from Biopsychology by Pinel.
You can't just ask people how much sleep they want. You have to test how they actually ARE, say by looking at white blood cell count, cortisol levels, memory retention, problem solving, and compare different baseline levels of sleep on such terms.
What I would like to know is what length of sleep a sedentary adult needs, whether that need N can be met by say (N' < N/2) at night and (N'' < N/2) during a day nap, and what (hopefully positive) affect can be had on reducing that need by say, exercise, diet, or sun exposure.
"... Far from our being chronically sleep-deprived, things have never been better. Compare today's sleeping conditions with those of a typical worker of 150 years ago, who toiled for 14 hours a day, six days a week, then went home to an impoverished, cold, damp, noisy house and shared a bed not only with the rest of the family but with bedbugs and fleas. ..."
I'm skeptical of this approach. I've had very poor results with eating whenever I feel like it, and continuing until my body tells me to stop.
Obviously, my ancestors didn't evolve in an environment in which they had continual access to an abundant food supply. I can't say for certain, but I suspect they didn't have unlimited access to sleep either.
> I've had very poor results with eating whenever I feel like it, and continuing until my body tells me to stop.
Poor comparison - I would guess what you ate could not be really considered food. That's were maybe the problem lies. Try to eat only healthy food - no compromises, no sugar, no junk at all - it is unlikely you will have bad results, even if you eat until your body tells you to stop.
> I can't say for certain, but I suspect they didn't have unlimited access to sleep either.
I reject the premise of your question - that it would be better if we did what our ancestors did - but I will just point out that not having artificial light (or an alarm clock) means that on average they likely slept much more than we do today.
My premise isn't that we'd be better if we did exactly what our ancestors did. My premise is that evolution has shaped us to deal with environments of scarcity and hard work.
The issue of light is a big one. Even with all the lights off, some street light comes in through the windows.
- get along with the way most of the world is organized and wake up every day roughly at the same time, and work/think/decide/learn below your capacity; or
- You do what is best for your mind, at the cost of an eternal impedance mismatch with the rest of the world.
We can't have both upsides at the same time, unfortunately...
I'm not sure if it's the accepted theory for sleep. I couldn't find references to it by name in journal articles, but perhaps it has another name. I learnt it from Biopsychology by Pinel.