Drinking too muchwatercan cause dizziness, confusion, and nausea when your intake exceeds what yourkidneyscan eliminate through urination. On rare occasions, severe fluid overload, or water intoxication, can even be fatal.
Too much water dilutes the amount ofsodiumin the blood needed for the body to function normally. Low sodium levels, known ashyponatremia, can affect many organ systems, most predominately thecentral nervous system.
Drinking too much water is rarely a problem for healthy people, but you don’t have to have an underlying kidney condition for this to affect you.
This article explains how drinking too much water can lead to dizziness and other symptoms, as well as serious complications.
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What Is Water Intoxication?
Water intoxication, also known as water poisoning, occurs when drinking too much water causes an imbalance inelectrolytes. Electrolytes are minerals in your body that have an electric charge and affect how your body functions.
Sodium is one of the most important electrolytes. This mineral has a number of vital functions in the body, including:
A healthy adult needs around 500 milligrams (mg) of sodium per day to maintain these vital functions.When you drink too much water, you not only reduce the ratio of water to sodium but also promote urination, which can clear sodium from the body.
Depending on your levels, you may develop:
How Much Water Leads to Water Poisoning?
In order for water intoxication to occur, you need to drink more water than you can excrete in urine. In healthy adults, the kidneys can excrete about a liter of water per hour.
With that said, the amount may be far lower if you havekidney diseaseor other medical conditions that affect urine output.
A 2021 study inBMJ Opensuggests that the median intake of water needed for water intoxication is 5.3 liters (1.4 gallons) over four hours.This is an average and not an accurate threshold for everyone.
Dizziness and Other Symptoms of Water Intoxication
Water intoxication often causes no symptoms. It is only when hyponatremia is severe that a person might experience notable and sometimes serious symptoms.
Mild symptoms of hyponatremia include:
When sodium levels drop below 110 mmol/L, water will start to enter brain cells and causes them to swell, leading tocerebral edema(fluid overload of the brain). This can lead to more serious symptoms, such as:
Hyponatremia can be very difficult to manage because it progresses so rapidly and the resulting damage can be severe. Also, it is important to reverse hyponatremia slowly, as overcorrecting can lead to neurological problems.
Causes of Water Intoxication
Hyponatremia, the main consequence of water intoxication, can occur when you drink an excessive amount of water and either have normal or low concentrations of sodium in your blood.
On the other hand, you might also have high-volume hyponatremia. This is when both your water and sodium levels are high but an underlying medical condition like kidney disease,liver cirrhosis, orheart failureimpedes the normal excretion of water in urine.
There are several situations that can contribute to the onset of water intoxication and hyponatremia, including weight loss, excessive sweating and fluid replenishment, and diabetes.
Weight Loss
The ideal amount of water for the average person is between 9 to 12 cups per day, depending on activity levels.Drinking anything more than this will unlikely increase weight loss.
As a general rule, thirst is a reliable indicator of the body’s water needs.
Performance Sports
It is normal for athletes to drink fluids to cool off and replenish water lost through sweat. However, when there is extreme physical exertion, thirst maynotbe the best guide.
Hyponatremia is common among marathon and triathlon participants due to excessive water intake and extreme sodium loss through sweating.
As such, performance athletes should obtain professional guidance to ensure enough water is consumed to avoid dehydration but not so much that water poisoning can occur.
Diabetes
Hyponatremia can occur in people withdiabetesdue to increased thirst (a common symptom of the disease). Uncontrolledhigh blood sugaralso contributes to frequent urination which can rid the body of electrolytes.
If your water intake exceeds the excretion of sodium and other electrolytes, hyponatremia can occur.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rangan GK, Dorani N, Zhang MM, et al.Clinical characteristics and outcomes of hyponatraemia associated with oral water intake in adults: a systematic review.BMJ Open. 2021;11(12):e046539. Published 2021 Dec 9. doi:10.1136/bmjopen-2020-046539MedlinePlus.Fluid and electrolyte balance.MedlinePlus.Low blood sodium.Office of Disease Prevention and Health Promotion.Dietary Guidelines for Americans 2020-2025.Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015 Mar;91(5):299-307.Popkin BM, D’Anci KE, Rosenberg IH.Water, hydration, and health.Nutr Rev. 2010;68(8):439–458. doi:10.1111/j.1753-4887.2010.00304.xDanz 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/NEJMc1510409Arampatzis 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
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rangan GK, Dorani N, Zhang MM, et al.Clinical characteristics and outcomes of hyponatraemia associated with oral water intake in adults: a systematic review.BMJ Open. 2021;11(12):e046539. Published 2021 Dec 9. doi:10.1136/bmjopen-2020-046539MedlinePlus.Fluid and electrolyte balance.MedlinePlus.Low blood sodium.Office of Disease Prevention and Health Promotion.Dietary Guidelines for Americans 2020-2025.Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015 Mar;91(5):299-307.Popkin BM, D’Anci KE, Rosenberg IH.Water, hydration, and health.Nutr Rev. 2010;68(8):439–458. doi:10.1111/j.1753-4887.2010.00304.xDanz 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/NEJMc1510409Arampatzis 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
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Rangan GK, Dorani N, Zhang MM, et al.Clinical characteristics and outcomes of hyponatraemia associated with oral water intake in adults: a systematic review.BMJ Open. 2021;11(12):e046539. Published 2021 Dec 9. doi:10.1136/bmjopen-2020-046539MedlinePlus.Fluid and electrolyte balance.MedlinePlus.Low blood sodium.Office of Disease Prevention and Health Promotion.Dietary Guidelines for Americans 2020-2025.Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015 Mar;91(5):299-307.Popkin BM, D’Anci KE, Rosenberg IH.Water, hydration, and health.Nutr Rev. 2010;68(8):439–458. doi:10.1111/j.1753-4887.2010.00304.xDanz 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/NEJMc1510409Arampatzis 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
Rangan GK, Dorani N, Zhang MM, et al.Clinical characteristics and outcomes of hyponatraemia associated with oral water intake in adults: a systematic review.BMJ Open. 2021;11(12):e046539. Published 2021 Dec 9. doi:10.1136/bmjopen-2020-046539
MedlinePlus.Fluid and electrolyte balance.
MedlinePlus.Low blood sodium.
Office of Disease Prevention and Health Promotion.Dietary Guidelines for Americans 2020-2025.
Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015 Mar;91(5):299-307.
Popkin BM, D’Anci KE, Rosenberg IH.Water, hydration, and health.Nutr Rev. 2010;68(8):439–458. doi:10.1111/j.1753-4887.2010.00304.x
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
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
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