Clearly hydration for sports is important – however when considering how to maximise energy whilst staying hydrated there are a few more things to understand.
The two main factors that contribute to fatigue during endurance performance are depletion of body’s carbohydrate stores and dehydration.
Sports drinks are either hypotonic, isotonic or hypertonic. This is determined by the carbohydrate and sodium concentration of the drink.
Hypotonic and isotonic drinks are designed to maintain hydration (isotonic drinks also supply some carbohydrate) whilst hypertonic drinks are used to supply energy via carbohydrate.
Hypertonic drinks are therefore designed for energy rather than hydration. Hypertonic drinks are best taken before exercise for energy and then to refuel.
The primary electrolyte lost through sweat is Sodium. If a large amount of Sodium is lost through sweating, the concentration of sodium in the blood drops which increases the movement of water into the cells leading to further dehydration. So sodium replacement in the right concentration is the key to rehydration.
If your hypertonic energy drink contains sodium and also high concentrations of carbohydrate the best strategy is to consume prior to exercise for energy and then for subsequent refuelling and then take on water with the right level of sodium to rehydrate.
The right level of sodium is dictated by how much sodium you lose through sweat and the rate at which you sweat. Some people are low salty sweaters whilst some people are high salty sweaters. These factors can be determined by a couple of straight forward tests. A high salty sweater who also sweats at a high rate may lose up to 1g of sodium per hour, which can severely impair performance. Such a person would want to supplement their hypertonic energy drink with water containing a high concentration of sodium to maximise endurance performance.