[jome]

Well, maintaining hydration with just water is not very easy, or even possible. It all pretty much comes straight through.

So yes, maintaining a good balance of salt and minerals, as well as hydration, is essential.

Personally I don't see (over)hydration as a huge performance boost, but it does pretty much eliminate packing blackouts. But there is such a thing as too much hydration IMO, so balance, like in everything, is the key...