Dietary Guidelines for Americans recommend that women consume 2.7L (91 oz.) of fluid and men consume 3.7L (125 oz.) daily. These are general recommendations for the public and will vary depending on unique individual needs. Two simple ways to monitor your needs include:

1. Weigh yourself before and after a vigorous activity/workout. For every pound lost, consume 24 oz. (3 cups) of fluid. The goal is to avoid weight/water loss during a workout, so aim to drink the amount necessary throughout your workout. For example, if you know that you typically lose 1 pound during a 60 minute workout, aim to consume 24 ounces of water before, during, and after exercise to replenish losses. (ie. 8 oz. 15 minutes before a workout, 8 oz. every 15 min during exercise, 8 oz. immediately following exercise).
2. Monitor color of urine. It should be plentiful and a pale yellow color.
   Hydration needs differ for each individual depending on: the amount and intensity of exercise, fitness level, age, gender, body size, and air temperature. It is therefore important to assess your unique needs through weighing and monitoring urine color, as recommendations vary for each individual.

Water versus Sports Drinks

According to the American Dietetic Association, water is the best fluid replenisher. Sports drinks are preferable to water when exercise duration exceeds 60 minutes or is at a high intensity, as they will help replace lost electrolytes and carbohydrates. Sports drinks are unnecessary for short-term exercise, and represent an unneeded source of calories for overweight individuals.

On a daily basis, we lose 10 cups of water simply from breathing, sweating, urinating, and meeting our metabolic needs; this is replaced by regular eating and drinking. In fact, 20% of our fluid intake comes from food. Foods such as celery, watermelon, peppers, cucumbers, strawberries, cantaloupe, broccoli, apples, and bananas are all high in water content.

Strategies to Prevent Dehydration

1. Always carry a water bottle and refill it several times during the day.
2. Freeze bottles for warm weather days.
3. Wedges of lemon or lime can improve the taste of water.
4. Other fluids such as juice and milk also count as fluid replenishers.
5. Consume foods such as fruits and vegetables, that are high in water content.
6. Minimize or avoid alcohol; as detoxifying alcohol requires a great deal of water.
7. Exercise indoors in warm weather and monitor hydration closely on warm days.
8. Rehydrate quickly if you feel dizzy, light-headed or very tired.
9. Never wear a rubber suit when exercising.

Signs of Dehydration

Waiting until you are thirsty may already be a signal that you are on your way to becoming dehydrated. Other warning signs include: flushed skin, premature fatigue, increased body temperature, faster breathing and pulse rate, increased perception of effort, and decreased exercise capacity. If dehydration worsens, more serious signs include: dizziness, increased weakness, labored breathing with exercise, heat exhaustion, and heat stroke.

References:

Cooper Institute. (2013). First Responder Fitness Specialist. Dallas, TX: The Cooper Institute

Hydrate Right. Retrieved Jan 21, 2014 from Academy of Nutrition and Dietetics website: http://www.eatright.org/Public/content.aspx?id=7084&terms=Hydrate%20Right

Larson, R.D. (2012). American Dietetic Association Complete Food & Nutrition Guide (4th ed.).Hoboken, NJ: John Wiley & Sons Inc.

Water: Meeting Your Daily Fluid Needs. Retrieved Jan 21, 2014 from Centers for Disease Control and Prevention website: http://www.cdc.gov/nutrition/everyone/basics/water.html