Look man, this is from wikipedia;
"Rehydration
In oral rehydration therapy, electrolyte drinks containing sodium and potassium salts replenish the body's water and electrolyte levels after dehydration caused by exercise, excessive alcohol consumption, diaphoresis, diarrhea, vomiting, intoxication or starvation. Athletes exercising in extreme conditions (for three or more hours continuously e.g. marathon or triathlon) who do not consume electrolytes risk dehydration (or hyponatremia)."
I insist that I should sip electrolyte (and also vitamin, why not?) "during" the exercise, because I have to replace the salt that I expel during sweating.. you know those white marks on your shirt or on your hat after they dry, they are the salts I mention.
So why not crushing "one-a-day" and dilute it in water and sip during exercise? Have you ever checked what's inside one "one-a-day" pill? All the minerals and vitamins you need, and with a really fair price corresponding to so called energizing drinks..