I'm sure most use water or gatorade. I use a big scoop of gaotade powder to help replenish simple carbs. Anyone use protien/creatine/glutamine mix? Heard it was benificial.
Gatorade has been proven in all kinds of article to increase endurance, but make sure to check serving size, as a 20 ounce gatorade has like 80 carbs in it.