When I was 20, I spent much of that year getting about 4 hours of sleep per night. I was in school at the time, and I was younger, and that sort of thing was more or less the norm. And somehow I was able to function that way. Maybe not brilliantly, but somehow I managed. I did well in school, and worked on the side, and found time to have friends. That isn’t to say it was fun; it did catch up with me from time to time. (Like the time I slept through a presentation my lab partner and I were supposed to give at our Experimental Methods class. The problem being that I had the poster.) But somehow, for the most part, I knew that as long as I had at least 4 hours of sleep I could make it through the following day. Painfully, perhaps, but I’d manage.
I’ve never been a big fan of the bona fide all nighter. I did that only rarely. Even so, I didn’t get a lot of sleep that year.
Until near the end of the academic year, when I contracted a very mild case of mononucleosis.