Nearly all the bio-chemical reactions that occur in the body’s cells depend on a balance between water and electrolytes(electrolytes being defined as a combination of sodium, potassium, calcium, chloride, phosphorous, magnesium, bicarbonate and sulfate). These balances are not only vital to maintaining life but also affect the body’s physical and mental performance..
Though it’s hard to say exactly how much water a person needs, a general rule of thumb is that a person should drink one ounce of water for every two pounds of their body weight. Since our bodies are predominantly made of water, an average person needs 8 – 9 glasses per day just to replace average losses. Caffeinated, alcoholic and many carbonated beverages have a diuretic effect and actually increase the daily fluid requirements. One should choose pure water or high quality sport beverages in most circumstances. It may come as a surprise to some that we actually lose significant amount of fluid by simply sitting in an air- conditioned car or office. Frequent drinks of water during a long automobile trip will reduce apparent road fatigue. The same applies to sitting at your desk
Daily fluid requirements will vary with environmental conditions, clothing, and the intensity and duration of exercise. Dehydration resulting from the failure to adequately replace fluids during exercise can lead to impaired heat dissipation, which can elevate body core temperature and increase strain on the cardiovascular system. Dehydration is a potential threat to all athletes, especially those who are not acclimatized for strenuous activity in hot environments. Even mild dehydration can create a reduction in muscle function. Early symptoms of dehydration include headaches, dry eyes, drowsiness, loss of concentration, and irritability. Studies have demonstrated that even at relatively low levels of dehydration, the time for a 1500 meter race was inhibited and the time for a competitive 10 K was seriously reduced. Muscle cramps are a more immediate sign of inadequate fluid replacement and electrolyte loss, particularly that of calcium and magnesium. In addition, thicker blood, fast heart rate, and negative changes in blood pressure can occur. To the detriment of many competitors in endurance sports, dehydration can lead to the diminishment of one’s “lactate threshold”, an indicator of maximal work performance ability. As the environmental temperature, exercise intensity and duration increases, you may want to switch to a quality sport drink with 6 to 8 electrolytes rather than just sodium and potassium to avoid a condition known as hyponatremia, or water intoxication caused by electrolyte loss and excess water intake.
Adequate hydration is very important in the maintenance of body temperature. When muscles contract they generate heat, which must be dissipated from the core to the body surface.
Don’t wait until you are thirsty to decide to drink water. Fluid replacement should be part of a daily plan. Thirst is a late sign of dehydration and performance is already impaired.
One last word of advice: cool beverages are absorbed better than room temperature or warm beverages.