As a universal rule, water is the primary source for rehydration for any athlete during a workout, event, or everyday life. However, When the revolutionary drink Gatorade was created for the Florida Gators football team, how to hydrate has become a seeming rivalry between the trusted water and the up and coming electrolyte drink. To answer the question which drink is better for an athletes body during intense spans of activity, a comparison of the overall goals and benefits of each must be examined. Water has been used as a tool for survival since humans have existed, mostly because it offers no serious nutritional setbacks. This, along with the fact that the majority of the human body is comprised of water and uses water to maintain body temperature, transport oxygen and nutrients, and dispose of waste, serves as a serious argument that water is the most necessary natural element for humans. Water offers a no calorie, easily absorbed solution to thirstiness and dehydration, and is a perfect source of hydration for athletes enduring extremely intense, shorter workouts.
However, the invention of electrolyte drinks wasn't just a marketing ploy to make quick cash. There are noticeable benefits to these drinks that water cannot provide. Sports drinks contain certain electrolytes and carbohydrates that need to be replaced in a long endurance workout. These drinks can replace these electrolytes and carbs that are naturally lost during a workout more effectively than water. Additionally, sports drinks are generally a more appealing taste to athletes, which in turn could lead to more consumption, which then leads to a quicker replenishing of the electrolytes and carbohydrates. Yet with these benefits, sports drinks also has some problems. The primary concern is the extra calories in every drink. Some drinks contain over 150 calories per drink, equivalent to 10 teaspoons of sugar, which can counteract the benefits gained.
However, a serious concern that must be noted is hyponatremia-- the rapid loss of sodium in the blood caused by over hydration. Yes, it is possible to over drink during workouts or athletic events. This can be done by drinking too much water and too much of a sports drink.
Overall, because sports drinks cannot defend against hyponatremia and also add unnecessary calories for a normal athlete, the general rule should be to stick with water, with the possible exceptions to long, high endurance activities. Yet even then water is still a very acceptable tool for rehydration.
Sources: http://www.health.harvard.edu/blog/trade-sports-drinks-for-water-201207305079 and http://runnersconnect.net/coach-corner/sports-drinks-vs-water-when-its-best-to-use-each/