The key for fluid absorption is consuming sports drinks that have an osmolality of less than blood plasma (<280 mOsm/kg).
Sports drinks claim to help athletes prevent fluid loss. Some experiments indicated that the two most popular sports drinks; Gatorade (374 mOsm/kg) and Powerade (417 mOsm/kg) have elevated osmolalities and as such will have delays in gastric emptying and absorption.
When the osmolality of a sports drink is greater than that of blood plasma the athlete may experience gastric distress such as cramping. Drinking just pure water during prolonged exercise will lower blood plasma and can also cause cramping. Therefore, a mixture of sugars/salt/and other electrolytes is also recommended.
Infinit, a sports drink made in Canada, has many different options for sports drinks that have an osmolality that is less than blood plasma (280 mOsm/kg).