Yes (I posted this before):
"We now also know that pre-industrial families commonly experienced a "broken" pattern of sleep, though few contemporaries regarded it in a pejorative light. Until the modern age, most households had two distinct intervals of slumber, known as "first" and "second" sleep, bridged by an hour or more of quiet wakefulness. Usually, people would retire between 9 and 10 o'clock only to stir past midnight to smoke a pipe, brew a tub of ale or even converse with a neighbor."
It's a natural sleep pattern. People used to wake up in the middle of hte night, hang out or have sex, and then go back to sleep.
Robb Wolff actually responded to this article here.
I've been doing 6 hours of sleep in the night and 1.5-hour nap in the evenings for almost two months. It's much better than 7.5 hours of sleep in one go for me.
There have been many questions already on Paleohacks in which people describe this bi-phasic sleep cycle. In optimal conditions, one can expect to wake up in the middle of the night with no ill effects.
I have the tiniest bladder ever and I wake up every night, without fail at 3am, even if I go immediately before bed. I have suffered no ill effects as long as I get 8 hours. It's what my body does naturally so I try not to get too wrapped up into others' suggestioms for my sleep.
Interesting. I think I saw another post here referencing the book they mentioned not too long ago.
I've found that I wake up once or twice through the night since I've begun sleeping on the floor. I usually chalk it up to me adjusting to my new sleeping style, but maybe I should get up and move around a bit and see how it goes. It would certainly be nice to get some study time in there. Maybe you can use candle light to put yourself in the nighttime mood.
I have always noticed that when I've fallen asleep while watching TV at times when I would usually be awake I wake up feeling very rested. Maybe this was acting as 'segmented' sleep.