[vanderZwan]

Naps are one thing, but the older I get the more I am under the impression that my body very strongly desires to follow a segmented sleep rhythm - I tend to get very sleepy in the late afternoon. Sadly that's a time filled with many activities that often make it impossible for me to "listen" to my body, so to speak, and if I stay awake I don't really get sleepy again until after midnight, which makes a long sleep during the night problematic.

However, when I actually have the opportunity to take a long afternoon nap, I sleep in two separate three-and-a-half to four hour periods. In my experience I feel much better rested when following this sleeping pattern than when trying to sleep in a constant eight hour block.

[Amadou]

I sleep in two separate three-and-a-half to four hour periods. In my experience I feel much better rested when following this sleeping pattern than when trying to sleep in a constant eight hour block.

Looks like there is historical evidence for a "first sleep" and a "second sleep" and that 8-hour stretches are a product of the last century or two.

http://www.nytimes.com/2012/09/23/opinion/sunday/rethinking-...

(hope the paywall lets you in)