Sleep is just the same as ever, say scientists

Including the question I was wondering about: do the authors think the historians who have argued medieval Europeans had segmented sleep were therefore wrong, and humans have never slept like that? The answer seems to be "no", but here the explanation gets to be what sounds, to me at least, plausible but a bit speculative,

[The historian Roger] Ekirch combed through centuries of Western literature and documents to show that Europeans used to sleep in two segments, separated by an hour or two of wakefulness. [Author of the present study Jerome] Siegel doesn’t dispute Ekirch’s analysis; he just thinks that the old two-block pattern was preceded by an even older single-block one. “The two-sleep pattern was probably due to humans migrating so far from the equator that they had long dark periods,” he says. “The long nights caused this pathological sleep pattern and the advent of electric lights and heating restored the primal one.”

There's an easy test that applies to yourself only though. Go to a place without tv/internet/books (electricity is fine) for a week, where you exercise outdoors and spend time with people.

I always end up sleeping 2-3h more (from 6h regularly to 9h!), wake up earlier, and sleep earlier - and in fact, feel better.

Most of the rest is just the stress inducing work/city life most of us zombies "have" to go through.

There are probably many other factors (for example, I sleep on the floor in Japan and use a "pillow" that is really just a sack of grain -- it might sound strange, but it is so much nicer than the overly soft trappings of western bedrooms IMHO). I had never really considered temperature as being a factor, though.

It seems to me that unrealistic expectations are the least dangerous issue in this situation.