美国国家队的游泳运动员Carly Geehr 在Quora上回答了这个问题：
「Nearly 100% of elite competitive swimmers pee in the pool. Regularly. Some deny it, some proudly embrace it, but everyone does.」
The more interesting question is *when* does said peeing happen?
Just about the only time you can get away with peeing during a race is during a breaststroke pullout. You spend enough time gliding that if you really gotta go, you probably could. Otherwise, you're too tense and too, well, busy to even think about peeing.Before a race is an interesting time. It depends on the meet and to some extent the color of the pool deck. I kid you not. You always try to pee before you swim, but sometimes your body defies logic and finds a way to refill your bladder just to spite you. Adrenaline and nerves wreak havoc on your system, and I knew tons of other swimmers that always, regardless of prior planning, had to pee right before a race. What to do if you're desperate? Well, it's not uncommon to splash yourself before you climb up on the blocks, 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.)Warmup/practice - totally free reign. As a swimmer, you just have to accept that you're swimming in pee. I had a teammate that would sit on the wall and announce "I'm peeing!" which was... disgusting... but at least she warned us. I'm sure I've swum directly behind people who were just letting it all out.
As to the underwater cameras catching it - even if Olympic swimmers peed during their races, which they don't - there's just no way. The only way you can really tell if someone's peeing in the pool is if they announce it to you or they're really dehydrated/sitting in one spot while they go. It diffuses pretty quickly, and if you're moving, it diffuses even faster. (Never been in a pool where they use those chemicals that makes pee turn bright colors, but have always wondered...)