Originally Posted by
terrymorse
Other than making your water taste even saltier, it doesn't appear that potassium is doing anything useful while you're exercising.
Sodium chloride (table salt), some sugar to help absorption, and some flavoring to make it palatable. The rest appears to be fluff and marketing.
I don't know how the concentrations in sports drinks compare, but the oral K supplements used in the clinical setting can be quite irritating to the digestive system. I also don't know whether it's the K salt, the high osmolarity from all that sugar, or what, but I often find Gatorade upsets my stomach on long, hot rides where I drink a lot of it.