• Numerous studies investigating water balance have demonstrated that the minimal water requirements of inactive adults who live in normal temperate climates are approximately 1 to 3.1 liters (or 34 to 105.4 oz.) a day. This amount should adequately replace estimated minimum respiratory, urinary, fecal, and insensible water losses.
• A general guide for replacing water loss is 1 liter (34 ounces) of fluid for every kilogram (2.2 pounds) lost, or 2 cups (16 ounces) for every pound lost.
• In more physically active individuals, the amount of water intake necessary to maintain proper hydration varies between 2 to 16 liters per day, depending on the activity and the individual. Physically active individuals are not necessarily athletes. Farm workers, heavy laborers, and the like naturally have higher needs for water.
• If you are planning a strenuous physical activity, drink approximately 2 to 3 cups of cold water 2 hours before activity. Drink 1 cup approximately 10-15 minutes before the activity or during your warm-up. During the activity, drink 3 to 4 cups of water every hour of activity, or 1 cup every 15 to 20 minutes. After the activity, you should rapidly replace the fluids that you lost within 2 hours. You should drink approximately 16-24 ounces of water for every pound lost during the activity.
• Cool beverages of 50-60 degrees are the best forms of fluid for the body. If an activity lasts longer than 1 hour, a sports drink is often recommended.
• Fluids with salt (e.g., sodium, potassium) are beneficial because they increase thirst. The salt also helps replace what’s lost through sweat. If you choose a sports drink, it should contain no more than 7% of carbohydrates per serving.
• Avoid fruit juices, carbohydrate gels, sodas, alcohol, and high-sugar sports drinks. These may dehydrate the body further by stimulating excessive urine production and/or decreasing your overall beneficial fluid intake.
source: JACA Healthy Living Fact Sheet April 2006