how much water to drink before a marathon
Susan Powell of Runners World recommends drinking 16 to 24 ounces of fluids -- either water or a mixture of water and sports drinks -- two to three hours before a half-marathon. This will give you enough time for your body to process the water, so you shouldn't need to go to the bathroom during the race. About 30 minutes before the race begins, consume another 5 to 7 ounces of liquid. This should be your last intake of water before the race.