During World War II, Field Marshal Rommel (of the German army) set forth to cross the Sahara Desert. He knew there would be a problem of keeping his soldiers physically capable of making the crossing and then putting them into battle. But before the crossing attempt, Rommel decided to experiment. He took three companies of soldiers and designated them as groups A, B and C.
Group A soldiers were ordered to march as far as possible without water; they marched just 10 miles. The soldiers in Group B were ordered to march as far as possible, but they were told to drink as much water as they wanted - Group B made 17 miles. Group C soldiers were told to march one hour, stop and then replace their weight loss with water. Every hour, on the hour, weighing took place and the soldiers were forced to replace that weight loss with the same amount of water. Group C soldiers marched 26 miles - 260 percent farther than Group A and 55 percent farther than Group B. This experiment shows that if we forcibly increase our fluid intake, we can perform much longer. Fifteen years ago and even today, many athletes were erroneously told to drink little or nothing before and during exercise.Further studies show that a 6 percent weight loss equals a 15 percent plasma loss. You may know that blood plasma carries nutrients. What happens if the effectiveness of plasma is lost? Simple, the body will not be able to perform. Dehydration causes plasma to lose its water and that affects all of the body's functions.
The easiest way to tell if you have enough to drink is to check your urine. Clear-colored urine in significant amounts indicates adequate hydration - as do the frequent trips to the bathroom. Dark-colored urine is concentrated with wastes and means you are dehydrated. If the body dehydrates enough, kidney and other bodily functions fail.
Dehydration affects performance. Water helps prevent dehydration, which further prevents heat exhaustion and heat stroke. If we can add water to our bodies, we can prevent problems. But how does it work?
The pyloric valve is at the entrance to the small intestine and acts as a flow controller. The small intestine allows some of the water and most nutrients to be absorbed directly into the blood stream. Most people average per hour about three-fourths of a quart of water flowing through the pyloric valve. In hot environmental conditions, the body can lose more water than it can absorb.
Replacing sweat losses of sodium, potassium and other electrolytes is probably a minor concern for most people. Unless you are competing in something like a triathlon, you are unlikely to deplete your body's stores of these minerals. The main purpose of the electrolytes in sports drinks is to enhance water absorption. Therefore, if you do require rapid fluid replacement, your best choice is a well-formulated sports drink that contains some sodium. Another point to remember is that our bodies require only 400 milligrams of salt per day, and we normally consume thousands of milligrams every day.
The best fluids are those that leave the stomach fast and contain little sodium and some carbohydrate or sugar (less than 8 percent concentration). Too much sugar reduces the flow rate through the pyloric valve. The flavored electrolyte replacement drinks contain about 5-8 percent sugar content.
What about soda pop? The sugar content of soda is even greater (about 10 percent) and therefore is not absorbed as well as water or the commercial sports drinks. What about fruit juices? Their sugar content ranges from 11 to 18 percent concentration and have even a greater absorption time. What about caffeine? Caffeine is a diuretic and thus may increase urination, this causing dehydration.
More fluids can be made to pass through the pyloric valve by drinking cold water, increasing the volume, and diluting to avoid high sugar intake. Studies have shown that cold water does not cause cramps. Cramps are generally caused from muscle energy consumption by-products not being taken away fast enough by the plasma.
Do not rely upon thirst alone to tell you how much to drink, since your thirst mechanism may not reflect your actual fluid needs. You may not feel thirsty but may still need more fluids. The better method is to check your urine, since based on thirst you may only replace half your water losses. Four percent (or more) dehydration is required before thirst appears. In other words, when you are thirsty, you are already 4 percent dehydrated.
It's important to remember the following:
- Five to six percent dehydration begins to affect the body (dizzy, shortness of breath, etc.).
- Water will prevent dehydration.
- Dehydration occurs faster than water absorption.
Drinking enough fluids is an important health practice. This practice will prevent the medical dangers associated with heat stress. Many Americans live day to day in a dehydrated state - that is, they don't drink enough water. An average person on a normal day loses between 3 and 6 quarts.
Three levels of dehydration occur:
- Mild: dry mucous membranes, darkened urine, thirst.
- Moderate: extremely dry mucous membranes, darker urine, thirst.
- Severe: mucous membranes as dry as paper, an altered state of consciousness (drowsy, irritable), no urine, no tears.
Dr. E.F. Adolph's research indicates that anyone standing in the hot sun needs three times as much water as those in the shade. His research refutes the idea that people stranded in the desert can increase their survival chances by dividing up their water supplies so as to stretch the water supply over a longer time period. The recommendation is to drink whenever you are thirsty, no matter how large or small your water supply is.