In preparation for difficult endurance exercise, drink 1 to 1.5 liters of fluid 2 to 3 hours before the event and .25 to .5 liters of water 10 minutes before start time. During strenuous exercise, drink as much fluid as possible. Ideally, .25 to .5 liters every 20 minutes. Do not trust your sense of thirst to reflect your need for fluid. Drink before you feel thirsty .
Water is always an excellent choice for the recreational athlete.
It is more quickly absorbed than juices or sports drinks. For those who exercise hard for 90 minutes or more , a beverage supplying 60 to 100 calories per .25 liter helps to supply the needed energy calories required for continuous performance. Diluted juices and sports drinks are good choices. Drinks with caffeine and alcohol act as diuretics. These are not good choices for fluid replacement.