There are 2 people I met in my life w/ significant stories about this..........
The first I experienced.......the other I wasn't there for.
First was a friend of my mother's. She rented this house w/ a guest house behind it that had a huuuuuge pool in between. We would play "Marco Polo" and the guy who lived in the guest house was just FREAKISH!!! I swear he'd hold his breath for 3 minutes or so. It was scary to say the least. I tried to go to the bottom and "hide out" w/ him once. I lasted about a 1.5 minutes and came up. He was still down there AT LEAST another minute.
Second was a buddy of mine who went to be an "Army Ranger"!!! Well, after rigorous training anyway, he also had to completely a dive test which was something like......(forgive me)........100ft (???) I can't remember exactly.
Anyway...........he burst both of his ear drums. He never completed the test and did not become a Ranger. Nothing wrong w/ holding his breath. He could hold it for 2:30 consistently........(also scary to me).
Heck, anybody remember the smoker on "Fear FActor" who made it thru the water-tube stunt at something like 2:3x ????. That was pretty sick, too!!