system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU/Marvel] How many hours a night does capt. America sleep on average?
gpt
He most likely needs to sleep occasionally, they never say that he doesn't and it's more about rejuvenating the brain rather than feeling tired. 

But I'd say on any give night, even without any sort of mission, he's more likely to be awake than asleep. If he is on mission, then his periods of wakefulness can stretch into weeks without really stopping to rest.

We know for certain that his ability to exert himself without "getting winded" extends into multiple hours. It likely goes further but he hasn't been pressed that hard.

But fatigue is different from being tired. It's just not addressed in any particular medium, other than he's awake whenever he needs to be (seemingly without much affect on his other abilities).

To answer the question explicitly I'd say less than one hour on average, because he goes for days and days and days without sleep and then gets in a few hours.