I am astounded these shift rotations are still going on.  There are huge amounts of scientific literature written on the detriment of this kind of scheduling.  When you don't get enough sleep, when you're biorhythms are throw off, when your sleep cycles are interupted this way, you're physically, mentally and emotionally far less able to do the best job you can.  Your immune system suffers.  You become ill more frequently and don't recover as quickly.  Your emotional wellbeing suffers.  I just can't understand why hospitals etc continue to schedule their staff members this way.  It's archaic.