While you may hear advertisements constantly encouraging you to drink more water every day, there is a point where drinking more water becomes harmful. Your kidneys are responsible for filtering water, but they have a limit as to how much they can filter during a certain time period. Exceed this amount, and you may experience symptoms of water intoxication, a condition that causes your cells to swell.
When working optimally, your kidneys monitor the amount of minerals like sodium and potassium in your body as well as the amount of fluids. If you have no known kidney impairments, your kidneys can filter about 800 to 1,000 mL or 0.21 to 0.26 gallons of water every hour, according to "Scientific American." Because one gallon equals 16 cups of water, you can drink about 4 cups of water every hour without causing a problem for your kidneys. However, there are some notable exceptions to these fluids recommendations if you have health conditions.
When you have kidney disease, your kidneys do not filter fluids and minerals as effectively as they once did. In this instance, your physician may recommend fluid restrictions to ensure you do not take in more than your kidneys can filter on an hourly basis. Your physician will determine your recommended intake depending upon the type of treatments you are undergoing, average daily urine output and if you are experiencing unpleasant symptoms like swelling. If you find you are gaining weight suddenly and have kidney disease, this can be a sign you are consuming too much fluid.
At rest, the body filters about 0.21 to 0.26 gallons of water an hour. In motion, however, your body releases a substance called antidiuretic hormone that keeps your kidneys from filtering as much water. This hormone is helpful when you are exercising because you do not have to stop often and use the restroom. In terms of fluid replacement, however, the hormone can make things confusing. While you are drinking more water to replace fluids lost via sweat, your body is not working as efficiently to release the remaining water in your body. This can contribute to a condition known as hyponatremia, in which you have more water in your body than you have salts to balance it.
While each person's water needs are different, if you are urinating clear to yellow-tinged urine and rarely feel thirsty, you are drinking enough water, according to MayoClinic.com. However, if you are drinking large amounts of water and experience symptoms like mental confusion, vomiting or sudden fatigue, these are all symptoms you have too much water in your body. Because this can lead to deadly brain swelling, seeking immediate treatment is vital to your health.
- 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
- "Scientific American"; Strange but True: Drinking Too Much Water Can Kill; Coco Ballantyne; June 2007
- DaVita: Fluid Control for Kidney DIsease Patients on Dialysis