Throughout the day we take regular sips on beverages to quench our thirst. To date, it has been recommended that the average person should drink 2400ml of water throughout the day.
However, guidelines of pre, during and post consumption of water is still in debate due to varying somatotypes. Nevertheless rough guidelines on fluid consumption prior, during and post an event have been depicted. The Journal of Athletic Training suggest that 2-3 hours prior to a running event 500-600ml should be gradually ingested. Furthermore, 10-20 minutes prior to exercise 200-300ml should also be ingested. However, these have been calculated on individual sweating rates and sports dynamic; therefore, these guidelines should only be roughly followed.
During an event it is suggested the the consumption of 200-300ml of water should be taken every 10-20 minutes. In similarity to the statements given above, the sweat rates and sports dynamics are used to calculate the water needed to efficiently hydrate the athlete. Hence, these guidelines should be used as a rough estimate.
For post exercise it is essential for the professional/recreational athlete to replace the fluids which have been lost throughout the exercise. Therefore, when evaluating you're water consumption needed for post exercise the immediate action of weighing your body weight prior exercise is needed to calculate the amount of weight loss caused due to the natural process of profusion. Overall, the measurement of 450ml-675ml of fluid per pound (0.5kg) of body weight lost during exercise is said to be the rough calculation to replenish the water levels within your body.
Casa, Douglas J., Lawrence E. Armstrong, Susan K. Hillman, Scott J. Montain, Ralph V. Reiff, Brent SE Rich, William O. Roberts, and Jennifer A. Stone. "National Athletic Trainers' Association position statement: fluid replacement for athletes." Journal of athletic training 35, no. 2 (2000): 212. American College of Sports Medicine, and American Dietetic Association. "Joint Position Statement: nutrition and athletic performance. American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada." Medicine and Science in Sports and Exercise 32, no. 12 (2000): 2130.