Both, facultatively. These days I’m a night owl, rarely to bed before 1 a.m., rarely up before 9:30 a.m. - I work a second shift and have for years.
But when I was young and keeping a “normal” schedule, I was the first one up and in the shower. Plus I was always alert and in good spirits immediately upon getting up. It’s possible I couldn’t get back to that, but I doubt it. I seem to be much more flexible about sleep schedules than average, even though I’m not one of those people than get by with only a few hours of slumber.
I have always been a bit of an insomniac though ( temporarily eliminated during the ~15 years I worked straight graveyards ) and I both enjoy mid-day naps and get my best sleep in the early morning hours after the sun has risen.