I'm not sure that's true, at least based on personal experience. I'm a long-time night owl who has been getting up relatively early for work purposes the last c

I'm not sure that's true, at least based on personal experience. I'm a long-time night owl who has been getting up relatively early for work purposes the last couple of years. I still do my best work late at night and struggle a little on complex tasks before noon. It seems like, while I can adjust my sleep schedule to whatever, the actual cycles of alertness have their own schedule that doesn't want to move.