Sports drinks are used to supplement the loss of electrolytes, water and energy after exercise, helping the athlete recover more quickly by replenishing key ionic substances in the body. They are designed to provide the athlete with equal amounts of carbohydrates and fluids to provide near-instant rehydration and replenishment during physical activity. This essay will explain the purpose of the contents of sports drinks and their use in the human body. There are three main types of sports drinks; Isotonic, Hypotonic and Hypertonic. A hypotonic drink will contain a lower concentration of sugars and electrolytes than a human body, meaning it would be absorbed faster than water. They contain more solvent than solute, meaning it would be less concentrated than inside a cell. Most sports drinks are classified as isotonic, meaning the concentration of electrolytes is similar to that found inside your cells and they will be absorbed at the same rate as water. These drinks contain equal amounts of solute and solvent, meaning they will be the same as those inside a cell. And finally Hypertonic, where the concentrate is greater than that present in the body fluids of a human being. Hypertonic drinks have the slowest absorption rate but offer the highest dosage of energy among the three. This drink contains more solute than solvent, resulting in a more concentrated solution. Sports drinks should contain 4-8% (4-8 g/100 ml) carbohydrates and 23-69 mg/100 ml sodium (American College of Sports 2007) to provide the best amount of fluid and fuel delivery . Studies have shown that sports drinks that contain proteins and amino acids (in a 2% concentration) provide superior recovery in specific exercise scenarios. (Stearns et al. 2010) Carboh...... half of the document ......AA, 2013) But which drink to use depends on what you want to achieve when practicing physical activity. If you are trying to exercise to lose weight, or are doing it in short periods (about 1 hour), water is the way to go. For most people, “fluid needs can be met by water” (Professor Clare Collins, DAA, 2013) and they generally do not sweat enough to lose many electrolytes. On the other hand, if you are an athlete and need to perform at your best for a longer period of time, sports drinks are the way to go. During physical activity, muscles use carbohydrate stores as fuel. These reserves will run out after about 90 minutes, at which point the fat will be used. Fat is not an efficient energy source and performance will decrease indefinitely. The carbohydrates found in sports drinks help keep athletes at peak performance for longer periods of time.