do they do?
They are designed to quickly replace the fluids which are lost by sweating, to prevent dehydration. They also provide a boost of carbohydrate to replenish energy.
Isotonic fluids are the most common drinks for athletes. They are particularly popular for middle and long distance runners.
does my body deal with them?
The body prefers to use glucose as its source of energy. Sometimes it is better to consume isotonic drinks where the carbohydrate source is a concentrated form of glucose.