Yeah, it's not by choice though. It can really mess people up if they're not aware of it. This NASA TED talk about time on Mars discusses how a different cycle can affect others too:
https://www.ted.com/talks/nagin_cox_what_time_is_it_on_marsEver since I saw that video, I've worked hard to (1) make sure others aren't negatively affected by my schedule (2) accept that until something brings me back to a 24-hour cycle, I have to persisently keep working on (1). Every other week I will go to bed at 10pm with my wife and wake up naturally at 5am and she'll have a great day being coordinated with my schedule. But within a week I'll be going to bed at 6am and waking up at 12-2pm. Every month or so I will stay up 30-36hrs without even trying.
None of this is due to bad habits, lack of sunlight, or lack of exercise etc. Doesn't matter what I do or don't do, my body just doesn't live in a 24-hour world. So I've learned to let it do its thing and work/sleep/eat/play when I feel like. Never been happier.
