How hot is it down there right now? Are you getting enough electrolytes? It almost sounds like your body is trying to overcompensate for something?? It sounds kind of strange. I'd be careful though... You don't want to go hyponatremic if your sodium levels are low.
I happen to be a VERY salty sweater so I really have to watch it. Esp. since I moved to the desert. After my long rides you could mill the salt off my face! We actually have a salt mill near here and my husband always asks me if I've been rolling in the salt piles again! OY!