1. 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. Hypotonic drinks give the athlete little energy in the form of sugars. A hypotonic sports drink is taken up by the body more quickly than just water. Ideal for recreational sports or shorter or less strenuous exertion.
2. 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. Ideal for endurance sports.
3. 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. Hypertonic drinks are taken up more slowly than water. Ideal for use 30 to 60 minutes before sports/training/exertion and immediately after sports/training/exertion. Hypertonic drinks are also useful for athletes or workers who find that they need a bit more energy during their training/competition/ exertion. Also ideal for less strenuous, long duration exertions such as studying, driving, gaming, etc.