Water is key to regulating body temperature by replacing the fluid that is lost during sweat, transport of nutrients, and promotes better blood flow. Fluids make up 70% of our lean body tissue and 60% of total body weight.
Staying hydrated also reduces the amount of sugar used by the muscles which in turn will promote better muscular endurance.
Sports drinks provide the additional carbohydrates and electrolytes needed with higher intensity training.
According to the ACSM (American College of Sports Medicine) guidelines, you want to drink approximately half of your body weight in ounces. So, for example, if you weight 150 pounds, you should be consuming 70-75 ounces of water per day.