One alternative take on it is that being continually engrossed with what you're doing can often stave off biological needs like food and sleep. When I was youn

One alternative take on it is that being continually engrossed with what you're doing can often stave off biological needs like food and sleep. When I was younger and would indulge in quite a lot of video games, there were nights where it would approach sunrise without feeling tired or hungry all night. Once I stopped to walk around I would feel myself get incredibly tired/hungry, but in the moment of being engrossed by an experience, it seemed to block everything out. As for darkness specifically, I wonder how active the subjects in complete darkness were, and what kind of reduction of mental activity occurs when you are not constantly processing optical information. Both would seem to me to reduce metabolism and presumably the need for sleep to some degree.