How much water do I need
Quick Tip: Drink to This. Do you know your sweat rate and, thus, how much to drink while cycling? Here's how to figure it. Weigh yourself naked before riding and then again after. Each pound lost represents two cups (16 fluid ounces or 480 ml). To this amount, add the quantity of fluid you drank during the ride. Take the total and divide it by the hours you rode. This is your hourly sweat rate -- the amount of fluid you should drink during each hour of riding for optimal hydration. Test yourself again when cool autumn weather replaces hot and humid summer conditions. (Source: Jenny Hagemann, MS, RD, in UltraCycling magazine, http://www.ultracycling.com)