- 1). Calculate the pace at which you want to run the race. A four-hour marathon takes around a nine-minute mile pace; however, a five-hour marathon is well more than an 11-minute mile pace. While both of these paces require considerable stamina, they don't require the same level of fluid replacement.
- 2). Consume 30 to 36 ounces of water and/or sports drink for every hour if you are planning to run your marathon in less than four hours, or at a faster pace than nine minutes per mile. During the course of the race, you should plan to consume as much as 4 liters.
- 3). Drop your replacement rate to 24 ounces per hour if you are aiming between four and five hours, or between nine and 10 1/2 minutes per mile, with a total consumption between 3 and 3 1/2 liters.
- 4). Reduce your fluid consumption further if you plan to take longer than five hours to finish the marathon. Plan for about 18 ounces per hour, not exceeding a total of 3 liters for the race.
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