way to go on completing your first metric!!! and ohhhhh do I know that "I fell like he!!" feeling...

if you fueled well, and recovered quickly, the only other thing I can think to add is to change positions on the bike a little more often maybe... I move from hoods, to drops, to center bar thru out rides... and at every stop I sit straight up and pull first one arm and then the other across my body to give it a chance to stretch a little... I also sometimes roll my neck at stops (which can result in you darn near falling over and looking like a complete dork so be careful with that one... yes, the voice of dubious experience here... )

and as mentioned, the heat can destroy you... I know some riders who are fine in heat and hate the cold... I would MUCH rather ride in the cold than the heat... rode one day last year and thought death was surely imminent... when I got home it was 102 degrees at 11AM!!!! took me 2 hours to recover that day!