I do 12 hour, 7p-7a, Sat/Sun. When I get off Monday AM I sleep about 4-5 hours, then keep a late night schedule and sleep 'til noon. I'm frequently on call so I am able to go in late nights if needed. I don't answer the phone when I sleep during the day, I have a beeper if I'm on call and they need to get in touch with me. If you want to survive nights, sleep has to be a priority.