[shinymoon]

Same here. I have always wondered how people can even wake up at 5 am, let alone focus and work.

In the mean time, I think, need for sleep is like appetite: some have more, some have less.

[narvval]

Waking up at 5 am doesn't imply sleeping any less (just going to bed earlier).

In the similar way, taking a nap doesn't mean that you sleep more, just that you schedule your sleep differently.