Worked midnights since 1989. You do get use to it. Sometimes too use to it. I find that on my days off, even if I am up all day, (so I can sleep at night) and no matter how tired I am during the evening, If I stay up past 10. My internal clock will wake me up and then I can't sleep for any thing. It will be 4 or 5 in the morning until I might fall asleep.