Plenty of Water is Not Good for Everyone! Common Misconceptions About Water Consumption

When more water is introduced into the body in a short time than the kidneys can excrete (1 liter per hour), the sodium (salt) ratio in the blood suddenly dilutes and drops to dangerous levels (Hyponatremia). Cells, especially brain cells, draw in water and begin to swell like balloons. This condition can cause severe headache, confusion, vomiting, seizures, coma, and even death (Water Intoxication).

It is vital for patients with Heart Failure, Severe Kidney Failure, and Advanced Stage Liver Cirrhosis to practice "fluid restriction." Because the pump (heart) or filter (kidney) of these patients is defective, excess water consumed cannot be excreted from the body; it accumulates in the lungs, drowning the patient, or causes massive swelling (edema) in the legs. The water limit of these patients is strictly determined by their doctors (usually 1-1.5 L per day).

The daily water requirement of a standard, healthy individual is proportional to their weight. The general medical formula is: 30-35 milliliters (ml) of water per kilogram. For example, a healthy person weighing 70 kilograms needs to drink about 2.1 liters (70 x 30) of water. On days involving sports, sweating, or extreme heat, this amount can simply be increased by half to 1 liter. Your best water indicator is the color of your urine; a pale yellow/transparent color proves that you are drinking enough water.