WE are bombarded by advertisements urging us to drink various types of sports drinks after sport to help us rehydrate our body. How do these drinks work?
Actually there are three types of drinks: hypotonic drinks, isotonic drinks and hypertonic drinks. A hypotonic drink generally contains less than 4g of sugar (carbohydrates) per 100ml and has low osmotic pressure. This is intended as a thirst quencher as it is taken up more quickly by the body than just water.
An isotonic drink generally contains between 4g and 8g of sugar (carbohydrates) per 100ml and has about the same osmotic pressure as bodily fluids. An isotonic drink is taken up by the body about as quickly as water. They are intended to quench thirst and provide energy to the body. A hypertonic drink generally has more than 8g of sugar (carbohydrates) per 100ml and greater osmotic pressure than bodily fluids. It is primarily intended to supply energy. The thirst quenching effect is secondary.