80% of the human body is made of water and therefore water is critical for our existence. It is important for your body to get adequate hydration or the body will not be able to function well. The intracellular space is filled with water based fluids. Water is also important to for the maintenance of a healthy concentration of the body's vital salts. Only when the electrolyte balance of the body is maintained, can the body function at its optimum.

Since water is also a critical element in excretion, and there is a lot of water loss through both sweat and urine, it is important to ensure that you keep replenishing it. Apart from the intracellular space, water is also found in the extracellular space. However, an excessive water loss can also cause dehydration, in which the water levels in the body get depleted.

Some of the most common ways of losing water from the body include:

  • Breathing in dry air can lead to the loss of humidified air. You can see the vapors from the mouth and nose when you exhale during the cold and dry winter months.
  • To maintain the body temperatures, your body sweats a lot. This can also lead to the loss of moisture from your body.
  • Water is also present in both urine and fecal matter. Water is therefore necessary for eliminating waste materials from your body.
This is a routine loss of water. With increased physical activity, the water loss is much more. Usually, the more weight a person carries the more water the body loses. Therefore, heavier people may need to replenish much more water throughout the day.