My work schedule is 6pm to 6:30am. I eat, sleep, poop, shower, etc. at consistent times workdays or off days. Maybe I'm not understanding circadian rhythms correctly, but keeping those things consistent is part of what I understand it to be. I have done what 99% of the people I've worked with on nights do and completely flip their schedule to a day schedule on their days off. Usually by staying up for more than 24hrs on their first day off and then going to bed 10-11pm. Some of them get home at around 7am, get in bed by 8am then wake up at 10-12 instead of just staying up.
I tried that. Trust me, if you think you've seen crazy, you haven't. I was on the verge of getting a divorce. By staying on the same sleep schedule I'm a much more agreeable person.
And it doesn't help that I work a 2-2-3 schedule. (Week 1 work Monday, Tuesday. Off Wednesday, Thursday. Work Friday, Saturday, Sunday. Week 2 off Monday, Tuesday. Work Wednesday, Thursday. Off Friday, Saturday, Sunday. Rinse repeat.) That schedule blows, hard.