This should contain a big fat caveat, this appears to be a very young person, maybe early 20's based on photos? My friend group could pull all nighters and 3-4 am weeknights playing beer pong just fine in college. When we have done so sparingly in our 30's the next day is completely shot so far as productivity, we can operate but at greatly diminished capacity.

I'd love to see the author try again in 10 years, I love comparing my current physical ability, e.g. number of push ups, chin ups etc, to where I was years ago, its a fun thing to see your body change over time.