When does exhaustion hit?

So I get that babies can possibly have their days and nights confused, Ally did, but what I don't get is why Matt has this thing about waking up at the wee hours of the morning and wanting to play! Last night (actually this morning!) at 1:30 AM he woke us up. I thought he was hungry, I made him a bottle, he didn't want anything to do with that so I put him to nurse. He didn't want anything to do with me. He was wide awake and wanting to play! He needed his diaper changed so I did and he thought being that "free" was funny. He was giggling like a fool. Thought that was the best thing. I put a diaper on him so I wouldn't get "wet" and we went to go swing. After playing, laughing, bouncing, swinging, and changing a poopie diaper at 4 AM he decided that he might be sleepy...thanks Matt! So we laid down. This morning I slept in by an hour and was not one to want to move. Thank god coffee is a wonderful thing. But I put this question to anyone out there. When does exhaustion hit? One day of this, several days or does it take months?
'Till Later