Water makes up about 60% of a male’s weight and 50% of a female’s. Two thirds of the water is held in our blood cells (referred to as intracellular fluid), the rest is outside (extracellular), and includes the blood plasma. Hydration has an important role in regulating body temperature, energy metabolism and cardiovascular stress. It is therefore vital to maintaining athletic performance levels. It can be fatal if we lose 9-12% of our body weight through water loss.
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What’s wrong with water?
Drinking plain water causes bloating, suppresses thirst and thus further drinking. It stimulates urine output and therefore is inefficiently retained. A poor choice where high fluid intake is required. Water contains no carbohydrates or electrolytes.
 
The Role of Water in Exercise
Body fluid has a critical role during exercise:
Blood carries carry oxygen and nutrients such as glucose to the muscles where they are required for energy metabolism. Oxygen is a critical limiting factor in the metabolism of energy.
Metabolic waste from energy production (eg: CO2) is removed from the cells by blood.
Hormones, which regulate metabolism and muscular activity are carried by the blood plasma
Water helps heat dissipation (through transfer around the body by blood and by production of sweat) as energy release generates heat
Sweat loss will also carry away minerals from the body which can have an additional impact on performance
Blood pressure, which affects the heart’s functioning, is significantly affected by blood plasma volume
Water loss at rest is primarily through urination. During exercise water loss increases dramatically and sweat becomes by far the most significant factor.
Ratios of Sports Drink to Water
Do not rely totally on your sports drink for water. A low glycemic sports drink contains 250 mg. or less of potassium per 16 ounces can be used in addition to your water intake at the following levels: you can use up to 8 (16 oz.) servings for a total of 128 ounces of low glycemic sports drink per 24 hour period and get the rest of your liquid intake from water.
All Water is Not Created Equal
Most tap water in America is polluted. EPA statistics show that 85% of all tap water is contaminated. Does that mean tap water will kill you? No, but it sure wont promote sports performance. Using bottled water is no guarantee that contaminants have been removed. Some bottled water is more polluted than tap water, and some bottled water is simply tap water. De-ionized water is recommended to mix your powdered sports drinks with, or when using bottled sports drinks. When de-ionized water is not available, distilled is second best. If you have water delivered to your home or office, call them and ask them to fax you data showing what type of water you are receiving. Many people are surprised to learn that bottled water delivered to their home is nothing more than filtered water. Try to find water that is de-ionized (reverse osmosis) and contains less than 12 ppm contaminants.
For those non-water chemists insisting that real water is unstripped water containing all the natural minerals, we recommend courses in biochemistry. If humans relied on water to supply the minerals we require, we would all be dead. Plants supply the minerals we require to sustain life, not water. Minerals come from the soil and not the water that hydrates the soil.