Granted, water overdose, called water intoxication, is possible, but it’s very rare and only occurs when you drink an unreasonable amount of water in a short amount of time, say three quarts or more in one sitting. Initial symptoms of water intoxication, such as drowsiness, lightheadedness, weakness, poor coordination, and mental confusion, resemble inebriety, which is where the condition got its name. In severe conditions, water intoxication can cause a throbbing headache, nausea, vomiting, convulsions, coma, and even death.

The situation occurs when a person consumes water faster than the body can excrete it. As hard as the kidneys work, they can be overwhelmed by a massive intake of water. As a result, the cells take up the excess water, which dilutes the concentration of sodium, an element that helps balance the acidity of fluids within the body’s cells. The diluted and swollen cells can’t function correctly. Cells in all parts of the body are affected, including the brain.

When water intoxication does occur, it usually accompanies other medical conditions, such as kidney disease, or psychiatric disorders, such as obsessive compulsive disorders. In contrast, most people don’t consume enough water, especially since thirst is not a good indicator of fluid needs. So, you can rest assured that drinking at least eight glasses of water every day is giving back to your body the essential fluids it needs to stay healthy.