The article also suggests that at least some people who have "trouble sleeping," may actually still be trying to replicate this older sleeping pattern, which seems to be closer to what nature intended for us. People who wake up in the middle of the night and can't go back to sleep aren't suffering from insomnia. They just don't know that after a couple of hours they are supposed to go back for second sleep!
And a sermonic note: this morning's sermon at First Presbyterian Church, Lowville, is from John 3:1-21 about the late night encounter between Jesus and Nicodemus, a respected Pharisee. Commentators and preachers sometimes make much of the fact that Nicodemus "snuck off" to see Jesus late at night as if he didn't want anyone to know. But, maybe Nicodemus there's nothing more to it than he went to chat with Jesus between first and second sleep. During the day, both of them were busy. Jesus, especially, had huge crowds following him around, so maybe it was just easier for Nicodemus to go see him between sleeps. Jerusalem wasn't all that big a place in those days, so it wasn't likely that Nicodemus could keep the visit a secret, and he may not have really had any reason to do so. It may be that nothing more is going on here than that he went to visit Jesus between sleeps, a time convenient for both of them,. Or, maybe not. We don't know, but it is fun to speculate!