Water is a critical element of the body and keeping the body adequately hydrated is a must to allow the body to function. Up to 75% of the body's weight is made up of water. Most of the water is found within the cells of the body (intracellular space). The rest is found in the extracellular space which consists of the blood vessels (intravascular spaces) and the spaces between the cells (interstitial space).
Through time, humans have constantly been searching for new experiences and tastes. Consequently new flavours have been added to water to create what we now call beverages - tea, coffee, soft drinks, fizzy drinks, sports drinks and alcoholic beverages – beer, wine and spirits. These all contain water and taste great but they also contain dehydrating agents. This means water is being taken out of the body creating a state of dehydration.
The body loses water on a daily basis through the kidneys (urine), lungs (water in expired air), skin (by diffusion and sweat), and intestines (feces).
So the cardinal principle of fluid balance is this:
Fluid Intake must equal Fluid Output It is as simple as that but we are talking pure water here not beverages!