I’m often awake for a few hours, e.g. between 2 and 5 am, or 1 and 4. Reading, or listening to the World Service, or downstairs making a cup of tea.
I will then often go into a deep sleep from say 4 or 5 am until 8 or 9.
Must be an age thing. Needless to say I usually need the loo a couple of times, too.
I look back wistfully to the days when I’d just go to bed and sleep soundly until morning.
I do quite often have a zizz on the sofa in the afternoon, but from experience I’ve found that whether I have or not, it makes zero difference.
Tea and coffee are strictly decaf after around 10 am, too, so it’s not that, either.