I guess it’s largely about geography and climate, the extremes being Nome, AK all the way to the equator helps forcing waking patterns. So does cultural habitat. My perception of living near the coast of New England seemed a saner rhythm. Then early in life when we transplanted to the cow country in the midwest, as in the whole workforce seemed to be tagged to farmers milking cows all day long, even though that general occupation is a tiny percentage of the workforce. Huh? Did anyone see what happened to the sun?

So all this early rising stuff is incentivized by the economic culture not necessarily by when people get stuff done or even feel productive. It’s about as real as daylight savings time, an economic construct not necessarily for the human race.

Yeah, if swing shift is your thing, do it. I’ve never milked a cow before the crack of dawn.