Sarah Schenker from the British Nutrition Foundation replies: Yes because they are absorbed much faster. These drinks have been specially designed so they contain just the right amount of salt and glucose to boost the rate of absorption and they also pass into the gut wall and blood quicker than water. The optimum composition of a sports drink is between 50-80g glucose and 55-100mg of sodium per litre. Anything above 80g glucose per litre (8%) drastically slows the emptying of the drink from the stomach into the intestine, as does the presence of too much salt. It's better to drink small amounts (about 100ml) every ten to 15 minutes rather than half a litre in one go because emptying time is delayed and it can be quite uncomfortable.