Sports drinks are beverages whose stated purpose is to help athletes replace water, electrolytes, and energy after training or competition, though their efficacy for that purpose has been questioned, particularly after exercise.
Sports drinks can be split into three major types:
Most sports drinks are moderately isotonic, having between 4 and 5 heaped teaspoons of sugar per five ounce (13 and 19 grams per 250ml) serving.
Athletes actively training and competing lose water and electrolytes by sweating, and expending energy. However, Robert Robergs, an exercise physiologist at the University of New Mexico who studied Gatorade, said that unless someone is exercising or competing in a sporting event for longer than 90 minutes, there is no reason to drink something with excess sugar and electrolytes. The Australian Institute of Sport states that excessive salt supplementation during exercise may lead to "gastrointestinal problems or cause further impairment of fluid balance" and may cause salt-induced cramps.