I know this is a little old but I had to post. TMI to follow... You have been warned.
This has happened to me a few times during an intense exercise session as well... The exact same rush of emotion and urge to cry has happened to me occasionally during particularly intense rolls in the sack with my hubby if you get my drift. I'm not one for crying either so I definitely attribute this to some random burst of some hormone.
Never hurt anyone to have a good cry now and then