Dunno.....I'm usually tired out by midnight but then I have to get up for work most mornings. During the holidays I slept till at least 11am every day for 2 weeks. There were a few late nights that didn't tire me much, but mostly I gravitated to bed by midnight. I suspect the job and the lousy weather and winter darkness had taken its toll on me and so I was just catching up on my sleep while I had the chance. I suspect that if I could get up at 11 every day, I'd eventually take to late nights like I used to when I was younger, especially when the warm weather and the light comes back. I was pretty active last summer compared to now.
It's hard to know because I've spent many years living with women who generally don't like it when I stay up late. It interferes with the sex life unless they care to follow my sleeping habits. They tend to think I'm deliberately avoiding intimacy. I tend to keep away from women who like late nights, though that's probably more to do with them liking night clubs and all the other night-life stuff that goes on, which bores and scares me. Might do OK with a lady who stayed up late without wanting to go out clubbing etc., once I've packed in my job.