Water

Water comes from different sources. Most foods contain water in its original form. An additional amount of water is produced after the process of digestion and oxidation takes place. In order to maintain normal body temperature, water as the body’s climate-control system, is released through sweat when the body temperature rises or heat is produced. The brain and kidneys manage the water balance. The hormones on the other hand, perform their roles as messengers in order to complete the process of elimination and replacement. If these losses are not replaced, dehydration occurs.

Dehydration is the most common problem of water imbalance due to water losses and deprivation. The effects of dehydration on nutrition can adversely affect ones health. Dehydration is the major cause of ones diminished ability to perform during endurance activities. Athletes are prone to dehydration because their thirst mechanism can not keep up with a large water loss from sweating and respiration. For this reason, proper water intake becomes very important during endurance activities.

Body water is lost through the stomach, respiration, sweat, and the kidneys. The kidneys are equipped with the mechanisms that control the elimination of waste products and have the ability to control water losses both at resting state and during exercise.

Water is also lost through breathing or respiration during exercise. This is because an increased exchange of oxygen and carbon dioxide takes place at this point. So, to make up for these losses, more water is produced by chemical reactions in the body. However, this process is dependent on the duration and intensity of work, the combustion of food during exercise, and the way the body uses the nutrients.

Water also binds to muscle glycogen, which is released when muscle glycogen is broken down. Remember when carbohydrates are not eaten, the body turns to its glycogen to break it down for the energy supply? The result is a big chunk of weight is removed from your body. Therefore, when you are fasting to lose weight, you will see a rapid weight loss. This "false" weight loss accounts for most of the water that was bound with glycogen because for every gram of glycogen, there are up to 4 grams of water bound to it. So, the more you fast, the more glycogen will be broken down, and the more water will be released.

Fluid Balance

Fluid Requirements:

• 20 ounces fluids - 1 to 2 hours before exercise
• 10-15 ounces fluids - 15 minutes before activity begins
• 3-6 ounces fluids - 10 to 20 minutes intervals during exercise that last more than 30 minutes

Fluid Replacement:

• 1 pound weight loss - two 8-ounce glass fluid
• 3 pounds weight loss - six 8-ounce glass fluid
• 5 pounds weight loss - ten 8-ounce glass fluid
• 8 pounds weight loss - sixteen 8-ounce glass fluid

Most beverages such as Gatorade contain less than 10% sugar concentration, which provides a quick glucose supply to the exercising muscles, thus slowing down the breakdown of glycogen. Some studies claim that if you drink a beverage that is more than 2.5% sugar concentrated, the result will be a rapid emptying of the stomach. Other research has reported that beverages that contain greater than 10% sugar concentration can cause nausea, diarrhea, bloating and abdominal cramps when taken, especially during exercise.

The recommended sugar concentration of a sport drink is up to 8%. The book entitled "Total Nutrition - The Only Guide You’ll Ever Need" by The Mount Sinai School of Medicine, 1995 gives you good information about nutrition, physical fitness, fluid requirements, and replacement.

-- Ofelia B. Mutia, M.S.,R.D.,L.D.

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