That's interesting what you said about your sweat being salty; is be interested in seeing how much electrolytes you're excreting that way. Conversely, my sweat isn't salty hardly at all, I've noticed. I wonder if there is any correlation, because I ride 50 to 60 miles, single speed on street tires, up and down elevation no problem with just regular water, never have had a cramp as far as I can remember. I don't consider myself a very fit person, and neither would a dietician, fwiw, so I'm not just some type of anomaly, just your typical desk dweller who hits the bike path hard on weekends when time allows.