Intake of fluids during training
Water serves many purposes in the human body, such as regulating the body temperature and acting as a transport medium for vital substances. A loss of fluid equivalent to only 2% of the body weight can substantially reduce performance. A loss of more than 5% creates the risk of nausea and cramps or convulsions, and life can even be at risk if more than 10% of fluid is lost.
Many sportspeople underestimate the importance of an adequate intake of fluids, so they misjudge the causes of muscle cramps, loss of strength and fatigue, leading them to draw the wrong conclusions.
The body must already become accustomed to an adequate intake of fluids during training. To achieve optimal performance, this means that it is essential to start training in a fully hydrated condition and to replace the fluid lost during training.
Ideal sport drinks
Sport drinks are usually isotonic. This means that they contain the same concentration of dissolved substances as the blood. The fluid and the dissolved substances therefore reach the bloodstream quickly. Hypotonic drinks, on the other hand, have a slightly lower concentration, but in return for this they are tolerated better by the stomach in most cases. Also the absorption of hypotonic sports drinks is slightly better than from isotonic drinks. Both isotonic and hypotonic drinks generally feature a wide sugar spectrum, resulting in a long-lasting supply of energy. For these reasons, you should pay attention to the list of ingredients when choosing your sport drink!
Another key factor is the sodium content. Sodium accelerates the absorption of carbohydrates into the bloodstream, which in turn causes water to be drawn in due to the shift in the concentration of the dissolved substances.