I think so. I spend a lot of time outdoors, even at night. When the sun goes down, there's not a whole lot to do. The eyes kind of shut down, the ears open and the mind follows the ears. It's not sleep but it's very much like it. The harder I concentrate the more my mind floats.

Waking is also different. There is no alarm. One wakes up and then has to kind of figure out what time it is. Maybe it's 3am or 5am. Until an hour or so before dawn, there's no way to tell.