Water

The natural choice for hydration is water. It hydrates better than any other liquid, both before and during exercise. Water tends to be less expensive and more available than any other drink. You need to drink 4-6 ounces of water for every 15-20 minutes of exercise. Water is the best, but it only helps you if you drink it.

Juice

Juice may be nutritious, but it isn't the best choice for hydration. The fructose, or fruit sugar, reduces the rate of water absorption so cells don't get hydrated very quickly. Juice is a food in its own right and it's uncommon for a person to drink sufficient quantities to keep hydrated. Juice has carbohydrates, vitamins, minerals, and electrolytes, but it isn't a great thirst quencher.