You need to replace the salts in your body if you're drinking large amounts of water. Sodium and potassium are what signal muscles to fire. If you drink excess

You need to replace the salts in your body if you're drinking large amounts of water. Sodium and potassium are what signal muscles to fire. If you drink excessive amounts of water without supplementing electrolytes, you end up with water toxicity, which can be fatal. Sports drinks are generally water with sodium chloride and potassium chloride added, often with sugar as well. Trust me, if you're sweating a lot and drinking a lot of water, you need a source of the appropriate salts.