..i'm going to experiment with my sleep. since i am retired i have nothing to loose and i must admit at least 50% of my sleeps don't make it through the whole night.
The forgotten medieval habit of 'two sleeps'
https://www.bbc.com/future/article/20220107-the-lost-medieval-habit-of-b...
For millennia, people slept in two shifts – once in the evening, and once in the morning. But why? And how did the habit disappear?