Earlier quoted context omitted.
There are plenty of studies on what night shift does to people who have a normal circadian rythym. It isn't pretty.
Yes, but is that the jet lag effect from repeatedly switching times or just being awake at night?
I seem to recall that working just regular night shifts (eg 2300-0700) will cut an average 5 years off your life. Rotating shifts with half+ during night is even worse.