I have commonly worked 12-hour swing shifts. This basically means that for a week or month I would work from 5 a.m. to 5 p.m. then I would switch and work from 5 p.m. to 5 a.m. for a designated period.
Changing shifts regularly took a little adjustment time, but the biggest obstacle I had to overcome was working the night shifts. When I switched from the evening/morning shift to the day shift, my body quickly made the adjustment. When I made the switch in the other direction, it was agony.
I know night shift work is a reality we are not likely to do away with, but it is not natural for the body. Working nights and sleeping days puts extra stress and strain on the body.