Segmented sleep?

[Mike ODonnell]

Thought this was interesting: (from a t-nation article of all places)

"In 2005, historian A. Roger Ekirch published a book named At Day's Close: Night in Times Past. In this book, Ekirch reveals what sleep looked like in pre-industrial times. Before there was electricity, before there were gaslights, people typically slept in two bouts they called first sleep and second sleep.

Within an hour or two after sunset, people would go to sleep, only to awaken about four hours later. Did they lie there and worry about taxes and their jobs and curse their circumstances? No, they got up and did household chores or visited with family or friends. They even used this time for sex.

Approximately two hours later, they'd go back to bed for another four hours or so.

Mind you, this was not social convention but innate physiology. It makes perfect sense, too, when you look at the rest of the animal kingdom. Almost all mammals that are active during the day, like chimps, giraffes, and yes by God, chipmunks, sleep in two distinct periods.

And when modern humans are freed from the time constraints imposed by modern life and modern lighting? They revert. Experiments where men are exposed to natural and artificial light for 10 hours a day and then confined to a dark room for 14 hours (similar to a winter's day and night) show that modern humans go back to segmented sleep. Likewise, anthropologists have observed similar segmented sleep patterns in certain modern African tribes."

Thoughts comments? I have to say I do find it interesting. Of course this assumes I go to bed at 7pm....which will never happen.

[Jeremy Jones]

If I get to bed at a decent hour (8-930) I will usually wake up again around midnight, and feel very well rested and alert. Usually, I try to go right back to sleep (I am already sleep deficient).

I attributed this to my usual habit of taking naps during the day, and to the adjustment of only getting 4 - 6 hrs sleep on a regular basis (terrible I know). Maybe there is more to this than I originally thought.

[Scott Kustes]

I can relate...If I get to bed by 9ish, I rarely sleep all the way through to 6am when I get up for work unless I'm sleep deprived. As long as I'm getting 8-9/night consistently, it is rare for me to make it past 3am without waking up. I promptly go back to sleep though once I look at the clock and thank my lucky stars that I still have 3+ hours.

[Yael Grauer]

That's interesting. I do know that some people would sleep through the night back then, without waking up... and the sleep studies indicate people got an average 9 hours throughout the year... more in the winter obviously.

[Mike ODonnell]

I'm glad I am not the only one who found this pretty realistic....as if I go to be early (that's 9-10pm for me) then I am usually always up at 3am...and here I thought I was suffering major sleep apnea...

In thinking about segmented sleep....maybe we were meant to sleep early....for 4-6 hours...just when our body is about to go catabolic and peak with cortisol levels, awak...refeed...get cortisol levels back down.....go back to sleep...and then reawake once again 4 hours later before cortisol levels get too high again. Is this a built in mechanism, and if so...that mean that sleeping 8+ hours in a row is actually more harmfull in the long run? (I remember reading about how most all heart attacks are early in the morning...right when cortisol is at it's peak)