Before a long run, a race, or a training workout, drink plenty of fluids. The day before an event, drink extra water, 100 percent juice and/or other nutrient-rich fluids such as nonfat or 1 percent milk. Monitor the color of your urine. The goal is pale yellow, not clear.
The morning of the event, drink 2 cups (8 oz.) of fluid two hours beforehand. This gives your kidneys enough time to process the liquids, giving you sufficient time to empty your bladder before the start of your event.
Thirty minutes prior to the beginning of the athletic event, drink another 5 to 10 oz. of water or sports drink. One oz. of fluid equals about a medium mouthful of water.
During Workout Hydration
Every athlete has unique hydration needs. By weighing yourself before and after exercise, you can estimate the volume of fluid your body requires to remain hydrated during exercise.
For each pound lost during activity, drink an additional 16 oz. of fluid. For example, if you drank 8 oz. while exercising for 60 minutes and lost one pound, your goal is to drink an additional 16 oz. during your next workout.
So, you would need to drink a total of 24 oz. to ensure proper hydration. This would equate to 6 oz. of fluid every 15 minutes.
To help you determine the amount of fluid you lose during exercise, you can weigh yourself before and after exercise. For each pound lost during activity, drink 24 oz. of fluid. If your body weight increased, you have overhydrated and you should drink less fluid in future exercise sessions.
After a practice or competition, drink to quench your thirst and then drink some more. Because the thirst mechanism is an inaccurate indicator of dehydration, you'll have to monitor your urine to determine whether or not you've had enough.