More on sleep

B reminded me about a fascinating phenomenon of the pre-electricity era: segmented sleep, in which people would go to sleep for three or four hours, then wake around midnight for a while, then go back to sleep until morning. The period between sleeps was not anxious, like insomnia, but could be very productive. I thought the NY Times ran a magazine cover story a few years back about sleep which mentioned this, and cited Benjamin Franklin as someone who came up with significant innovations during the wakeful hours in the dark, but the only piece I can find is this one. I woke up at 3:40 this morning and thought of it, all excited - it would be great to be able to use that time! I have woken before in the night, but usually do feel anxious. That could be because I thought I was costing myself sleep, though...