Yes, yes they do. All of them. Liberally.
"As a swimmer, you just have to accept that you're swimming in pee," said Carly Geehr, a former member of the U.S. national swim team.
Answering the question on the Q&A website Quora, Geehr said "nearly 100 percent" of elite competitive swimmers regularly do it, mostly because they can't help it. "Adrenaline and nerves wreak havoc on your system, she said, "and I knew tons of other swimmers that always, regardless of prior planning, had to pee right before a race."
Turns out, most swimmers are too tense and distracted to attend to their bladders during an actual race. Instead, they get the job done during warm-up, or utilize a crucial interval just before the race begins: "[It's] not uncommon to splash yourself before you climb up on the blocks," she explained, "so that extra liquid on yourself and the pool deck affords you an interesting opportunity. (I'll let you finish the rest of that thought.)"
In case you wanted specifics, the otherwise-studly Ryan Lochte is an unabashed pool-peer.
When asked whether he engages in the activity on an Aug. 3 radio interview, the 11-time Olympic medalist said, "Of course. I think there's just something about getting into chlorine water that you just automatically go. [I didn't] during the races, but I sure did in warm-up."
He sure did.