A friend of mine used to work days. Then a month later - nights. Month after that it was swing.
Lather, rinse, repeat. Every 30 days.
It was brutal. By the time he got used to one routine, it was time to change.
I knew some Air Traffic Controllers in the service overseas. They had them working 6 on, 12 off. They would work 4 different shifts over a 3 day period. Their goal of more alert, rested controllers produced zombies. Always tired, and their digestive systems all out of whack.