Fluid And Hydration

By: Laura Casselman, CPT

For those who participate in a regular program of exercise, hydration maintenance should be a top priority. Keeping adequate amounts of water within the cells of the body prevents dehydration, which causes earlier than normal fatigue as well as loss of coordination and skills. Exercise performance will begin to suffer when as little as 2% of body weight is lost due to perspiration. Therefore, loss of body fluids should be monitored as an essential part of a healthy exercise program.

In order to prevent dehydration, exercising individuals must drink plenty of fluids before, during, and after working out. Relying on thirst as an indicator of how much fluid is lost is not an accurate method, since studies show that thirst is a sign of dehydration. People exercising must therefore take prevention measures and not wait until they are thirsty to drink. Most people have no idea how much fluid they need, let alone how much they have lost during the day or during exercise.

There are two easy ways to monitor fluid levels:

• Weigh in before and after a workout. Consume two to three cups of fluid for each pound of body weight lost.
• Check urine color. A dark gold color is a sign of dehydration while a pale yellow color, or no color at all, signifies one is heading towards a state of hydration. Those who consume a lot of caffeine or alcohol, which are diuretics, will have pale or clear urine even though they are, in fact, dehydrated. Use of diuretics must be taken into consideration when checking urine for hydration.

Most experts will now recommend sports drinks to exercising individuals, especially if their workouts last longer than 60 minutes. Sports drinks do maintain physiological function as well as, if not better than, water. However, consumers of sports drinks must pay attention to the number of carbohydrates in each drink. Drinks containing less than 5% carbohydrates do not provide enough energy to enhance performance, and beverages containing 10% carbohydrate or more are associated with intestinal cramping, nausea, diarrhea, and impaired absorption.

Exercisers should follow these guidelines for fluid replacement.

• Consume one to two cups (8 to 16 ounces) of fluid at least one hour before the start of exercise. If possible, consume 8 ounces of fluid 15 to 30 minutes before the start of exercise.
• Consume 4 to 8 ounces of fluid every 10-15 minutes during the workout.
• Consume 16 to 24 ounces during the 30 minutes after exercise, whether thirsty or not.