Literally staying up all night. It sounds like you're getting plenty of sleep. It doesn't matter if you sleep all day or night if you're adhering to some kind of schedule and sleeping enough. With a night schedule though, you risk giving up sleep for early morning appointments, classes etc. Missing sleep might start a manic episode or just make you feel tired! Mania/hypomania usually involves staying up all night or only needing a few hours of sleep per night. Personally, I might stay up for a couple of days, sleep and do it again. I can get on a 48 hour day as opposed to a 24 hour day cycle. So I'd be hypomanic while being able to sleep 8 or 9 hours at a time but, at most every two days. It's fun!