What is the RDA for a person riding a bike for hours in the hot sun and humidity? The RDA on the label is for the general population, not endurance athletes. Until we know how much of the different electrolytes we lose with exercise, we will have no idea how much to replace, and relying on a baseline for people NOT exercising is a misleading figure at best.

Just think about it logically - Gatorade (and others) tells everyone that sweating a lot means that electrolytes need to be replaced (with their products, of course), but their products actually have very small amounts of those electrolytes. If their products are indeed effective for electrolyte replacement, it must mean that only small amounts of electrolytes are lost and need replacing. If that is the case, then a very small amount of regular food will do the same thing, which means the only benefit to Gatorade is the convenience. If, however, more than very small amounts of electrolytes need replacing, then their products must be ineffective.

Finally, regarding problems from having too much potassium via a supplement, eating a couple bananas would introduce a lot more potassium into one's system and we should have all heard the dangers from eating bananas while riding instead of how beneficial they are.