I feel fine now; I got maybe 7 hours last night. I’ll probably start feeling sleepy in a few hours if all I do is write on the computer. It doesn’t seem to matter how much sleep I get, though. I get sleepy if I’m sitting, and I am fine if I am doing something physical.
I can function quite well on 4 hours, but I prefer not to do that. This is different from maybe a decade ago. Up until then, I absolutely needed 7–9 hours every night. Something changed after that and about three years ago, I had a manic episode and I barely got two hours of sleep per night for a long time. If I’d had someone to stay up with, I probably never would have gone to sleep. It wasn’t really fun, except in retrospect. It feels like I could have played all day and all night if the conditions were right. But maybe the past is always that way.