Requirements of water for Human Body: Daily Input and Output

REQUIREMENTS

Requirements of water varies with climate, dietary constituents, activities and surface area of the body. As a rule a person should take enough water to excrete about 1200 -1500 ml of urine per day. In tropics because of greater water loss through perspiration increased water intake is required to maintain urine volume. Normal intake of water ranges between 8 - 10 glasses per day.

Daily Water Input

In tropical countries like India the daily water input amounts to 2400 - 3000 ml of water through food, as fluid drinks and as metabolic water.

1.       As fluid drinks - water, tea, coffee, 

          milk soups  1500  - 1750 ml

2.       Water intake through solid food       600    -        900 ml

3.       Oxidation of carbohydrate, fat,         300    -        350 ml

          proteins (metabolic water)                         

                                      Total 2400 - 3000 ml

Daily output of water

1. Urine      1200  - 1500 ml   (kidney)

2.       Perspiration         700    -        900 ml        (Skin)

3.       Respiration 400 ml                           (lung)

4.       Faeces         100    -        200 ml                  (intestine)

Total 2400 - 3000 ml

Therefore the water intake and output is fairly kept constant. This is called water balance. The average adult metabolises 2.5 - 3.00 litres of water and a constant balance is maintained between intake and output. Inadequate water intake disturbs water equilibrium resulting in decreased urinary output, thereby causing changes in Extra Cellular Fluid (ECF) and Intra Cellular Fluid (ICF). The water equilibrium is maintained by kidneys, lungs, intestine and pituitary gland. The water balance coordinates with both electrolyte and acid base balance.