I’ve heard that as a common complaint about PE, but showering was not the norm at my school. In middle school we started changing and the lockerroom had showers, but no one used them. In high school it was pretty much the same thing. Only jocks would (rarely) shower after classes and even only when they had morning class. No one changed their underwear either. It was “gay” to have your shirt and shorts off at the same time.
I heard this story the other day and thought about starting a GD about whether or not gym class really contributes to anybody’s health. I don’t know if that would have worked. 
Anyway, in my high school, we had gym on alternating days - three days a week, then two days a week, etc. I liked sports and enjoyed the class most of the time, although getting sweaty and then sitting through physics or math was gross. Most of my friends hated it, and I’m not surprised it isn’t too popular on the Dope. In principle, I have to say I still support the idea of gym. Half an hour to an hour of exercise two or three or five days a week could make plenty of difference. But it’s also true that if you want to get through the class without doing anything, you can.