Sports drinks, such as Gatorade or PowerAde, contain electrolytes such as sodium and potassium. When you're running, your body loses electrolytes through sweat. Since electrolytes help your body retain fluids and may prevent muscle cramps, you need to replace them when running more than 90 minutes.
Runners who don't sufficiently replace electrolytes during long runs or races can risk over-hydration. Hyponatremia, which is low blood sodium concentration, can occur when athletes drink excessive amounts of water and don't replace salt lost through sweat.
The basic rule of thumb for hydrating during runs is 6 to 8 ounces of fluids every 20 minutes. During runs of more than 90 minutes, you can alternate between sports drinks and water. So, every other hydration break, you should be drinking a sports drink. For shorter runs, hydrating with plain water is fine.
Another benefit of sports drinks is that they contain carbohydrates. Since it's necessary to consume calories during runs of longer than 90 minutes, drinking a sports drinks will help you take in some of these needed calories. Some runners find that it's sometimes easier to get their calories through liquids rather than solid foods, especially during the later stages of a long run or race.
