Water composes 66 percent of the human body and is needed for a number of body functions, including filtering minerals out of your body and making up the blood. This is why physicians and fitness experts emphasize drinking water. However, there is a flip side to drinking water. Excess amounts can place too high a demand on the kidneys, which can result in death.
Water Drinking Cases
Drinking too much water -- a condition known as hyponatremia or water intoxication -- is common among endurance athletes who use water to rehydrate after a marathon or triathlete, according to "Scientific American." Deadly cases of drinking too much water have been documented as a fraternity hazing prank or as a water-drinking contest hosted by a radio station. An awareness of how and why excess water affects the kidneys can reduce the incidents of illness and death related to water loss.
Kidney Function
When functioning normally, the kidneys work to monitor your fluid intake and regulate the amount of salt in the body. Your body naturally needs both sodium and water to function properly. Sodium rests outside your cells and is used for energy, communication and fluid balance. The kidneys are made up of a series of intricate loops that have sensors to determine how much water, salts and other substances should be eliminated from the body.
Excess Intake
When excess water intake backs up, your kidneys cannot keep up. This means the water builds up in your blood. The water moves outside your cells where it ultimately enters the cells, making them swell to capacity. While cells are flexible, they are much like a balloon that will swell and burst. Ultimately, if the kidneys can't keep up, you will have less sodium and more water. This can make the brain swell, which ultimately leads to adverse effects like seizures, coma and brain stem herniation.
How Much Is Enough
Your kidneys cannot keep up the pace when your blood sodium concentration is below 135 millimoles per liter. The kidneys maintain a very delicate water balance that should be between 135 and 145 millimoles per liter. When it drops even a small amount below this number, you can begin to experience adverse symptoms. Your kidneys can filter about 800 to 100 ml -- 27 to 33 oz. -- every hour. If you have been increasing your water intake, be aware that symptoms like headache, nausea, fatigue, vomiting, disorientation and frequent need to urinate can indicate you are experiencing water intoxication. Note that water intoxication can result due to an increased release of antidiuretic hormone combined with excess water drinking. This combination occurs in stressful situations, such as while running a marathon. Your brains signals your body that because it is under stress, you should conserve water. Carefully regulate your intake if you are an endurance athlete or drink an electrolyte-containing beverage, which has salt in it.
References
- "Scientific American"; Strange But True: Drinking Too Much Water Can Kill; Coco Ballantyne; June 2007
- MayoClinic.com; Water: How Much Should You Drink Every Day?; April 2010
- Go Ask Alice!; Is It Possible to Drink Too Much Water?; July 2007
- Dr. Ben Kim; Why Drinking Too Much Water Is Dangerous; Dr. Ben Kim; February 2011
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