Maintaining adequate hydration during physical activity is one of the most important nutritional methods to optimize performance.
Due to the wide disparity in body size, activity and environmental conditions, there is no one fluid recommendation that will suffice for everyone. In fact, the 2007 American College of Sport Medicine (ACSM) position stand on hydration recommendations are as follows: "Due to individual differences in sweat rate, it is difficult to provide a single hydration recommendation".
To determine your own sweat rate, simply weigh before you exercise and after. For every 1% of body weight lost, you should replace with 16-24 oz fluid. The goal is to ultimately minimize loss of body weight (i.e. dehydration), but to avoid taking in too much fluid during exercise.
Studies show that athletes who enter competition in dehydrated states, have decreased performance. During competition a 1% drop in hydration/body weight may cause a 3-4% decline in muscle performance.
For exercise longer than 60 -minutes, sports drinks are recommended. Some researchers even suggest that there are benefits to using sports drinks for exercise over 30-minutes.
The best sports drink is the one that you like to use the most! If you perspire heavily, you might consider a higher sodium sports drink like the ones listed below. Some sports drinks contain carbohydrate and protein. Whichever formula you choose, it is important to try it out several times in training before using it on race day.