A coworker of mine, who exercises regularly, was telling me that her daughter deliberately avoids exercising. The reason, the daughter said, is because she learned in health class that sweat is the same as urine, so when you exercise and sweat, you're basically peeing all over your body.
This made both of us laugh, and we weren't sure if it was just an excuse or a legitimate fear based on misinformation. I don't know if it would change the daughter's mind, but I thought I'd try to find some accurate information for her.
This daughter is in her early teens, so I thought internet sources might be more persuasive than scholarly journals. I searched the web for "is sweat like pee" and immediately hit on answer forums all saying no.
Sweat does contain a small amount of uric acid, which might have accounted for her logical leap, but they are definitely different fluids.
There is certainly more thorough research that could be done for this question, but I left off here. It might be a tall order to convince her that sweating is actually a good thing.