Can't say I fully understand electrolytes (or anything else scientific), but I do know that for any mtb ride 1 hour or longer I do not do well with only water. Generally I mix a very light gatorade, powerade, or similar drink. I find gatorade is quite loaded with salt, so other brands tend to satisfy me better. Actually, one time I mixed red bull with water. *that* was a fun ride! I don't know why this works for me exactly, but it's what I need for decent energy.

Hugs and butterflies,
~T~