(On mobile so I can't really load up much for articles, so the rest is based on an assumption about what you linked regarding segmented sleep in the past.) My

(On mobile so I can't really load up much for articles, so the rest is based on an assumption about what you linked regarding segmented sleep in the past.) My old business partner used to pull it off quite effectively. His girlfriend was an early to bed, early to rise type and seemed to require more sleep than him. They'd go to bed around 9 or 10. She'd sleep through to 6. He'd sleep through to about 4, get up and screw around on the computer for a couple of hours, go back to bed, and then get up again at 8. Got to go to bed at the same time as his girlfriend, got an extra couple hours of productive time in the night, got up at his regular time. It was, to me, a pretty ingenious solution within his constraints. Unfortunately I'm the "if I'm up, I'm up" type. Takes me a bit of work to get conscious but once I do I won't sleep again until my bed time.