How Much Water Is too Much?

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It is important to stay hydrated. However, excessive fluid consumption does not contribute to your well being, and may even cause health problems.

Excessive fluid consumption can cause fluid overload, or water intoxication, which may lead to serious health consequences—swelling of the brain, brain injury, and ultimately stroke—leading to disability or even death.

It is not only the amount of water consumed that causes overload—water toxicity is caused by drinking too much water too fast. Most people who overdose on water are not aware of the consequences. Drinking too much water may initially produce mild consequences, and then, if the situation continues, dangerous health effects may occur.

The Consequences of Drinking too Much Water

Your body works to maintain normal function despite the regular variations that you experience throughout the day. The first way your body manages water overload is by simply getting rid of the excess fluid through urine. This means that if you drink too much fluid, you will balance out your body's fluid by urinating more. If you repeatedly drink more water than you need, then your body should be able to efficiently remove the fluid, and you will end up constantly peeing.

If you notice that you are constantly peeing and constantly thirsty, this can be a sign of diabetes (a problem with your pancreas that results in a buildup up blood sugar.) Your body manages the buildup of blood sugar in a very complex way, and frequent urination and constantly feeling thirsty are among the earliest signs of diabetes.

Central Nervous System Symptoms

The rapid consumption of large amounts of water overwhelms the body’s natural ability to maintain normal fluid balance. This causes excess fluid to enter into the brain, resulting in brain swelling. Symptoms may include:

  • Confusion
  • Headache
  • Drowsiness, lethargy
  • Dizziness (vertigo): Reported in 14% of patients with severe hyponatremia
  • Severe symptoms include sudden unexpected loss of consciousness, seizures, or stroke.

As well, the dilution of sodium in the bloodstream (hyponatremia) also contributes to symptoms such as nausea, vomiting, or muscle cramps.

When the body takes in extreme amounts of fluid, the excess water literally flows into the brain cells through a process called osmosis. This causes brain tissue compression and lack of normal function. Brain cells may experience a disruption to their normal calcium and sodium concentration and begin to function abnormally. This results in the symptoms that may include lightheadedness, dizziness, or confusion.

Some brain cells may die from physical compression and some from the electrolyte and water imbalances. This condition—hyponatremia—is very difficult to manage medically because it progresses so rapidly and the damage is so severe.

Causes of Drinking Excessive Amounts of Water too Fast

There are, in fact, some circumstances that set the stage for water overdose.

Health Cleanse

The idea of drinking water because it is pure and devoid of calories is popular among dieters and health enthusiasts. Overall, water has many benefits when it comes to healthy living. But the advice to 'drink more water,' doesn't apply to everyone.

The ideal amount of fluid consumption for an average person should be between 9 to 12 cups per day.

People who already consume enough water do not need to drink more. In general, thirst is a reliable indicator of the body’s water requirements. Some health conditions such as diabetes and kidney disease may disrupt your normal thirst mechanism and necessitate a consultation with a dietitian or physician to set guidelines for fluid intake.


It is normal for athletes to drink fluid in order to replenish and cool off during and after a training session and it is important for the body to stay hydrated during exercise. However, in the setting of extreme physical exertion, thirst may not be the best guide. Hyponatremia due to excessive drinking has been seen among marathon and triathlon participants. Devoted athletes who work out beyond moderate levels should obtain professional guidance regarding appropriate fluid replenishment.

Water Games

These activities often seem silly or harmless to young people. Yet some actions that seem innocuous may be quite dangerous. Preschool-aged children and older kids—even as old as college-aged young adults—may think it is funny to challenge each other to drink large amounts of water or other liquids (such as alcohol, which contains mostly water) quickly. But these fun games have unfortunately been known to harm some of the kids who participate in them.

Water overload has been responsible for incidents of brain damage and death in children, teenagers and young adults who play games involving exaggerated fluid drinking or who use rapid consumption of excess water or fluid in hazing and initiation rituals. The outcome is usually shocking to young witnesses, which can further delay appropriate medical attention and treatment. Thus, the damage may be permanent paralysis, mental incapacity or death.

A Word From Verywell

Most of the time, good for you means good for you. However, in some instances, too much of a good thing is really too much. Diets that can help you lose weight can have negative effects on your overall health. And, surprisingly, you can even overdose on harmless and healthy things such as water and vitamins.

The key to a healthy lifestyle is balance and moderation. Take care of your health by seeking out trustworthy and reliable sources.

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  1. Peechakara BV, Gupta M. Water toxicity. [Updated 2019 Sep 30]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2019 Jan.

  2. National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes insipidus. Published October, 2015.

  3. Arampatzis S, Frauchiger B, Fiedler GM, Leichtle AB, Buhl D, Schwarz C, Funk GC, Zimmermann H, Exadaktylos AK, Lindner G. Characteristics, symptoms, and outcome of severe dysnatremias present on hospital admission. Am J Med. 2012 Nov;125(11):1125.e1-1125.e7. doi: 10.1016/j.amjmed.2012.04.041

  4. Rondon H, Badireddy M. Hyponatremia. [Updated 2018 Dec 13]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2019 Jan.

  5. Popkin BM, D'Anci KE, Rosenberg IH. Water, hydration, and healthNutr Rev. 2010;68(8):439–458. doi:10.1111/j.1753-4887.2010.00304.x

  6. Danz M, Pöttgen K, Tönjes PM, Hinkelbein J, Braunecker S. Hyponatremia among Triathletes in the Ironman European Championship. N Engl J Med. 2016 Mar 10;374(10):997-8. doi:10.1056/NEJMc1510409