As I was sipping my bottle of "Smart Water" in the Dojang this morning a fellow student asked me why I purchased "Smart Water" so I continued to explain to him that it has electrolytes without all of the sugars etc. of other sports drinks. His comment to me was that he felt it was a waste of $$ because tap water contains electrolytes... I have found no evidence to prove or disprove this. Anyone got some feedback?
Drinking water contains all sorts of electrolytes unless it was first distilled or de-ionized. However, there are different types of electrolytes. There are strong electrolytes and weak electrolytes, cations and anions. Also, "sport" drinks should at least aim to restore the electrolytes that we lost by sweating during workouts. Their concentration and type might be different from what you get in your tap water or bottled water. Our cells require a balance of Sodium (Na+) and Potassium (K+) cations. We lose a lot of these ions with perspiration and urine. Hence we need to restore that balance after or during the workout.
Tap water will contain electrolytes, simply because it's expensive and not worth removing them as is most cases they aren't at the levels that will do you any harm. Even bottled spring water does too, just read the label.
As Blade said the sports electrolyte drinks are supposed to be designed to have the right kinds and amounts of electrolytes to hydrate you faster. Hence the total amount of electrolytes are higher than bottled water.
Regarding Smart Water though. If it's the same type as is available here. It's not an electrolyte drink. It's basically flavoured water with some vitamins and antioxidants and maybe gurana thrown in. Considering one 500ml bottle of Smart Water contains 37% of your RDI in sugars they're not particularly good is this aspect either. You're probably better off drinking powerade.
500ml Coca Cola = 215 calories
500ml Smart Water = 138.5 cal
500ml Powerade = 114 cal