Water Intoxication

Water intoxication definition

Water poisoning or water intoxication is a condition wherein an individual suffers from a drop of sodium levels in their blood due to drinking water excessively. This is a life threatening condition. Drinking 2 liters water every hour, for a few hours successively can lead to water intoxication. Now this does not occur accidentally or all of sudden – it happens when you end up drinking many liters water in just a few hours, resulting in consuming about 10 liters water in a day. There are various signs and symptoms which can help you understand if you have water intoxication – seizures, headache, swelling of feet and hands, vomiting, coma, or eventually, death. There is a medical term of water intoxication – dilutional hyponatremia. The main causes are water poisoning and water overdose.

Water Intoxication

Chronic water intoxication and acute water intoxication

For acute water intoxication condition, the sodium levels of blood fall down under 1330 mmol per liter (milli moles per liter) in about 2 days. For chronic water intoxication, the sodium levels of blood drop down to the same in more than 2 days.

Early signs and symptoms: the very initial symptoms for water intoxication appear when the sodium levels in blood drop down below about 130 mmol per liter. Let’s have a look at some of them:

  • Difficulty in concentrating
  • Irritability
  • Restlessness
  • Dizziness
  • Nausea
  • Diarrhea
  • Headache
  • Vomiting
  • Muscle weakness
  • Dizziness
  • Fatigue
  • Unstable gait

It is important to understand that if you have clear urine, it does not mean you have water intoxication because one can always have clear urine regardless of whether they are hydrated or even overhydrated.

Late symptoms in case of severe water intoxication: once the sodium levels of the blood drop below 105 mmol per liter, the following symptoms will appear after the above mentioned ones, ranging from a few hours to a few days:

  • Drowsiness
  • Blurred vision
  • Shaking
  • Tremor
  • Muscle cramps
  • Coma
  • Coughing blood because of lung edema
  • Delirium
  • Agitation
  • Confusion
  • Hallucinations
  • Seizures – unusual grimacing and jerky movements of the limb
  • Swelling of feet and hands, ascites (abdomen), especially with alcoholics
  • Decrease in urination
  • Collapse
  • Death (in about 2 days post these symptoms)

Note that the quicker the sodium levels in blood drop, the more severe will the symptoms get.

Signs of Water Intoxication

  • Bradycardia – slowing of the heart rate
  • Hypothermia
  • Decorticate posture – rigid posture in a way that arms are bent inwards to the body, fists are clenched and hands are held on your chest.
  • Bluish discoloration in hands and lips – Cyanosis is caused because of pulmonary edema.
  • Dilated pupils – both sides
  • Increase in blood pressure (hypertension) or decrease in blood pressure (hypotension)
  • Sudden drastic increase in body weight to several kgs, but it’s not constant. For example, someone who is earlier dehydrated, even if they keep drinking a lot of water, they might still be dehydrated and hence will have lower body weight than normal, but they can also be suffering with water intoxication.
  • Respiratory arrest – decrease in volume and frequency of breathing.
  • Pulmonary edema – increase in frequency of breathing.

The short term effects of water intoxication on body organs include rhabdomyolysis (muscle breakdown), pulmonary edema (lung swelling), and cerebral edema (brain swelling). Let’s take a look at the long term complications in the body. A severe hyponatremia episode can leave a permanent brain damage in person, which can result in any of the following:

Cerebral palsy

  • Diabetes insipidus
  • Gait abnormality
  • Hearing loss
  • Mental retardation
  • Vegetative state, persistent

The main cause of having water intoxication is intake of large amount of water or any other drinks containing very little or nil amount of sodium – fruit juices, sports drinks, coffee, soft drinks, tea, beer, or consumption of food with lower sodium content. Let’s take a look at the factors that can be responsible for increasing the risk for water intoxication:

  • Low intake of sodium especially during starvation or fasting
  • Sex in females
  • Diabetes mellitus when not controlled properly along with ketoacidosis
  • Lower body weight in children, infants or petite women
  • Retention of water can happen because of several reasons – liver cirrhosis, kidney failure, kwashiorkor (malnutrition and poor intake of protein), hypothyroidism, Addison’s disease (adrenal insufficiency), nephrotic syndrome (a disorder of the kidney where there is a protein loss via urine), or any other hypproteinemia causes. Apart from these, NSIAD (Nephrogenic syndrome of inappropriate antidiuresis) which is a rare disease, genetic in nature affecting male infants can also be the reason. Moreover, SIADH (Syndrome of inappropriate (excessive) secretion of the antidiuretic hormone) can also be a cause of water retention. Here, kidneys fail to excrete out excessive fluid and its causes include stress, lung disorders, severe pain, marathon (exercising for a prolonged time), surgery, drugs, cancer, or brain disorders.

Pathophysiology or mechanism of water intoxication

When you are over-hydrated, and there is a decrease in sodium levels in blood, known as hyponatremia, it leads to decrease in blood osmolality. The mechanism of osmosis is that water moves from lower space to higher osmolality space. Hence, in the body, it moves into your body cells and even your brain cells, leaving them swollen. Cerebral edema or brain swelling leads to compression of the brain in the tight human skill. This is the result of symptoms for water intoxication which eventually leads to death. Let’s take a look at some medical cases of water intoxication and some cases reported by the media:

Using water diet for losing weight

Attempting to quickly lose weight by restricting the diet to a very limited number of things along with drinking huge amount of water and thereby having a very low sodium content in the body for suppressing appetite can lead to fatal hypinatremia. A case in 2008 has been reported where a 40 year old woman was on such a diet for restricting calories that she ended up consuming very less salt but tried to compensate it by drinking lots of water. After following this for a week, one day, she drank almost 4 liters water in about 2 hours. This led her to have a severe headache, collapsed and lost consciousness. The next day, she was reported dead in the hospital.

SIADH – Syndrome of Inappropriate ADH Secretion

ADH (antidiuretic hormone) is responsible for preventing water loss from your body by inhibiting the urination. In some cases, even when there is normal hydration in the body, ADH gets secreted in excessive amounts. This leads to retention of water and eventually in hyponatremia. This condition is called SIADH or syndrome of inappropriate ADH secretion. Some of the common causes of this include certain lung disorders and brain disorders, medications (drug carbamazepine, chemotherapeutics or antiepileptic drug), or cancers.

Cystic fibrosis

Cystic fibrosis is a rare genetic disease. The people suffering from it tend to lose massive sodium amounts via sweat, hence they are more vulnerable to developing hyponatremia post drinking water.

Using water as an attempt for hiding drug abuse

Many people who are into drug abusing tend to drink a lot of water to attempt diluting their urine samples by drinking lots of water a day prior to the drug testing. Such kind of urine formed will have lower specific gravity which is really easy to identify in drug testing, hence it is not really a smart way to cheat your way through it. Back in 2003, a case was reported where a 43 year old man ended up drinking 19 liters (5 gallons) water in addition to 20 capsules of diuretic Uva ursi (or bearberry which is known to stimulate excretion of sodium). He did this just a few hours prior to his drug test. He was also smoking marijuana, was lethargic, but did not have any seizures. He was eventually successfully treated with the help of 3% saline’s intravenous infusion.

Water intoxication of infants, child abuse and drinking games

water intoxication can occur in infants when the baby formula is diluted too much. Apart from that, forcefully making children drink water is a punishment form which is child abuse. A case reported in 2002 of a 4 year old girl in Utah, USA, states that her parents forcefully made her drink about a gallon that is, 3.8 liters of water in her. She died in just a few hours. In 2012 in Sweden, a twelve year old girl drank 6 liters water while playing poker. The game was that every player, upon losing had to drink a glass full of water. She died within a few days. Similar cases have been seen for various drinking games and drinking contests. Many people have been reported to have died for drinking as much as 7.5 liters water in just a few hours. Such cases have been reported for colleges and frats.

EAHE (Encephalopathy) and EAH (Exercise-Associated Hyponatremia) for triathlon and marathon athletes

If runners drink massive amounts of water, as much as 1.5 liters or more per hour, they can end up developing hyponatremia. It could be either water, any other beverages or and commercial sports drinks, none of which contain sufficient sodium amounts. Here are some other risk factors and causes of hyponatremia which is exercise associated:

  • Extreme hot weather which leads to excessive sweating and thereby drinking excessive amounts of drinking water.
  • Taking NSAIDs (non-steroidal anti-inflammatory drugs) like ibuprofen or indomethacin. These drugs are responsible for sodium loss along with urine and retention of water. In these terms, one can consider taking acetaminophen as it is much safer.
  • Hardcore exercising for over 4 hours.
  • Athletes, especially female athletes who have lower body weights and high rates of sweating including massive salt losses during sweating.

Two cases have been reported where hyponatremia lead to death. In 2002, a 28 year old woman while running for the Boston marathon died due to drinking huge amounts of some commercial sports drink. Other than that, in 2005 in Washington of USA, a 25 year old man drank 11.4 liters (3 gallons) water during and post 12 mile bike ride.

Hypotonic fluids containing very little or no amount of sodium infused intravenously

Hypotonic fluids containing less sodium (lesser than blood), like D5W or DW5 (5 percentage dextrose in water) when infused intravenously can cause hyponatremia. ADH’s (antidiuretic hormone) release increases resulting in retention of water, however there is normal excretion of sodium. Hence, if a person after surgery gets intravenous infusion, they might develop hyponatremia.


Using water from the tap for enema can lead to causing dilutional hyponatremia – this especially happens with infants. It can also happen to adults and children. Cleansing the colon by water prior to barium enema may also lead to water intoxication. A case was reported where a 3 year old boy got hyponatremia post colon irrigation using plain water.

Beer Potomania

The amount of sodium content in beer is extremely low, hence drinking lots of beer while consumption of food, thereby a lower sodium intake for the body leads to hyponatremia. People who are chronic alcoholics are known to suffer prom protein malnutrition. When there is low sodium level in blood, it leads to lower osmotic pressure along with lower levels of protein and lower blood oncotic pressure – all of this resulting in water movement into brain cells from blood, (commonly known as blood edema) and also in body cavities (ascites or distended abdomen). A case was reported in 2002 where a man, about 30 years old was used to drinking about 12-oz cans of beer (10 liters) every day without eating anything straight for days. He ended up becoming confused, yet remained conscious. At the time of examination, his abdomen had become distended and his hands shaky. The level of sodium in his blood was 105 milli moles per liter (the normal level is about 135 to 145), blood serum osmolality came to 225 mOsm per kg (the normal level is about 280 to 300), and urine osmolality came to lesser than 1.005 (the normal level is about 1.010 to 1.025).

Amphetamine or MDMA (Ecstasy) use

The people used to taking stimulant drugs like amphetamine or ecstasy can even dance for many hours straight – hence, they end up losing lots of sodium and water via sweat. These drugs are also responsible for stimulation of thirst, and secreting ADH, and hence leading to retention of water. All of this when combined along with drinking massive amounts of water leads to hyponatremia. Lots of cases of people dying from taking ecstasy, drinking huge amounts of water (about 7 liters in less than 2 hours) and dancing for several hours have been reported.

Heat related illness leading to overhydration

In 1996 to 1997, many soldiers from USA suffered hyponatremia along with nausea, confusion, seizures, or vomiting post drinking more than 2 liters water in order to avoid stress due to heat.

Compulsive water drinking or Psychogenic Polydipsia

Many people suffering from schizophrenia or any mental disorder can end up drinking about 15 liters water in a day. This condition is called psychogenic polydipsia or compulsive water drinking. In 1980, a case was reported where 20 people suffering from psychogenic polydipsia and schizophrenia lasting to 28 months were evaluated for having hyponatremia. This happened because of drinking water in the range of 7 liters to 43 liters in a day. These people had their sodium levels in blood in range from 98 mmol/L to 125 mmol/L (the normal level is from 135 mmol/L to 145 mmol/L).


There are certain medications which stimulate retention of water along with (and/or) excretion of sodium. Both of these situations can lead to hyponatremia if they are taken with massive amounts of water. Let’s take a look at some of such medications:

  • Barbiturates
  • Opioids, like morphine
  • Antidiabetics – chlorpropamide
  • Desmopressin spray is an analog of ADH used for the treatment of enuresis (bed wetting) for children
  • Antipsychotics, like haloperidol
  • Drugs for lowering Cholesterol, like clofibrate
  • Anticonvulsants (antiepileptics), like phenytoin, sodium valproate, and carbamazepine
  • Chemotherapeutics, like vincristine
  • Diuretics, like furosemide, thiazides, and indapamide
  • Antidepressants like SSRIs, monoamine oxidase inhibitors, and TCAs. A case was reported where an 82 year old man was taking mirtazapine (tricyclic antidepressant) and ramipril (ACE inhibitor). He got confused post drinking 3 liters water in about 4 hours – for the urine flow study preparation. Once he reached the hospital, he was diagnosed with hyponatremia and was treated successfully.
  • Apart from the above mentioned ones, here are some others – amlodipine, antibiotics like ciprofloxacin and trimethoprim sulfamethoxazole, amiodarone, proton pump inhibitors like omeprazole, and ACE inhibitors like losartan and lisinopril.

Gastric lavage

Gastric lavage when combined with massive amount of water, plain, can lead to absorption of water and eventually, hyponatremia.In May 1995, as per a report in Forensic Science International journal, a 21 year old girl died post gastric lavage in combination with 7.8 liters water in about 2 hours.

An attempt at suicide

Many people have attempted killing themselves by drinking excessive amount of water.

TURP Syndrome (transurethral resection of prostate)

The water absorbed from irrigation at the time of endoscopic prostate retention, or in rare cases, at the time of other different endoscopic procedures (for example, arthroscopy, cystoscopy, and percutaneous nephrolithotomy) may lead to at times fatal hyponatremia – all of this about 15 minutes to a day post the procedure.

Other health conditions with similarities of water intoxication

There are several other health conditions which have certain similarities to water intoxication. Let’s take a look at each of them in detail:

Water Intoxication Symptoms

  • Water intoxication’s symptoms are coma, headache, increase in urination, vomiting, agitation, confusion, seizures, and unsteady gait. The signs include swollen feet and hands, sweaty or dry skin, clear urine, normal range skin turgor, and increase in body weight.
  • Severe dehydration – the symptoms are coma, thirst, headache, nausea, fatigue, and confusion. The signs include dark urine, decrease in urination, delayed skin turgor, dry skin, and a decrease in body weight (more than 5%)
  • Heat exhaustion – the symptoms of this condition include fatigue, headache and thirst. The signs of heat exhaustion include increase in body temperature (about 37 to 40 degree Celsius), increase in heart rate and breathing rate, and sweaty, pale, and cool skin.
  • Gastroenteritis – the common symptoms of this condition include abdominal cramps, diarrhea, and vomiting. All the signs of dehydration can be experienced for this condition as well.
  • Kidney failure (chronic or acute) – the symptoms of kidney failure are changes in volume of urine, vomiting, anorexia, fatigue, and nausea. The body swells in this case, known as edema.
  • Alcohol intoxication – the common symptoms of this condition are unsteady gait, vomiting, disorientation, fatigue, and coma. An alcohol odor could be a sign of alcohol intoxication.
  • Lung edema in addition with left heart failure – the symptoms are chest pain, weakness, dyspnea (difficulty in breathing), and fatigue. There is an increase in breathing rate and a decrease in sounds of breathing at the time of auscultation.
  • Nephrotic syndrome – the signs and symptoms include fatigue, no edema and a normal blood pressure.
  • Cerebral salt wasting syndrome – the symptoms of this condition are headache, agitation, and lethargy.
  • Adrenal crisis or insufficiency – the symptoms are salt craving, fatigue, skin pigmentation, weight loss, and abdominal pain.
  • Liver cirrhosis – The symptoms and signs of this condition include fatigue, ascites (abdominal swelling), and fatigue.
  • SIADH (syndrome of inappropriate ADH secretion) – the signs and symptoms include weakness, nausea, headache, no edema and a normal blood pressure.
  • Myxedema coma (hypothyroidism) – the symptoms are feeling cold and fatigue. The signs include increase in body weight, swollen lower legs, dry, cool skin, and a decrease in body temperature.

Lab Tests and Diagnosis for Water Intoxication

  • Urine test: low sodium for SIADh. For high sodium (more than 20 mmol per L). For low osmolality, lesser than 100 mOsm per kg and for SIADH in cases of high osmolality, more than 1200 mOsm per kg. Also for lower specific gravity, lower than 1.010 and for SIADH, higher osmolality, more than 1.032.
  • MRI (magnetic resonance): through MRI, brain swelling can be revealed.
  • Blood test: for lower than 135 mmol per L sodium levels. Also when the other electrolytes are generally in normal ranges and in case of lower than 275 mOsm per kg osmolality. In acidosis as well.


Water Intoxication Prevention & treatment


If you are planning to run a marathon or a triathlon, or if you are planning to participate in kind of endurance events, drink only till your thirst, avoid taking NSAIDs starting 24 hours before the event to 6 hours after completion, and have healthy food. Before and after a few days of the event, try to eat regular, salty food so that they could help building up the body sodium levels. Never overhydrate before an event. One should also not go for salt tablets at the time of the event because they can end up affecting sodium levels of the blood leading to stomach cramps.

First aid

It is important to differentiate dehydration from overhydration, when a person complains of severe headache, seizures, or vomiting. For a person who has severe dehydration, they will have a significant reduction in their body weight; about 5%. They also have delayed skin turgor. For a person who is overhydrated, they can have either normal or elevated body weight. If they have exercised for a prolonged duration, there could be a slight reduction in their weight, and occasionally, they might have swollen feet and hands. If a person is overhydrated, what you can do is to try and calm them down if they are agitated. Do not, in any cases, offer them anything to eat or even drink. Next, call the ambulance.


for treating water intoxication in cases with severe symptoms like seizures, there could be salt and water restriction, like in the case of hypervolemia, high protein diet, arginine (AVP) vasopressin (ADH), salt tablets in case of hypovolemia, IV fluid infusion of 3% saline, antiepileptic drugs (anticonvulsants), antagonists (tolvaptan, conivaptan, and demeclocycline), and furosemide (diuretics). Chronic hypenatremia is treated slowly. In this case, the sodium levels in blood are made to rise in a way slower than 0.5 mmol per L per hour. If this is not followed, it can lead to severe neurological complication, like central pontine myelinolysis.


Generally, water intoxication can be treated effectively without any consequences. However, there are some prognostic factors which are bad – hypoxia, pulmonary edema, women at the time of childbearing, sodium levels in blood below 105 mmol per L (in which case the mortality is up to fifty percent), and Pneumococcal meningitis.

Water Intoxication Frequently Asked Questions

  • Can water intoxication be painful?
    The people who look up ways of committing suicide can have this concern. Severe cases of water intoxication come along with nausea, exhaustion, severe headache, and seizures. Water overdose leading to severe hyponatremia or treating hyponatremia has the have the risks of permanent neurological disability.
  • What is the amount of water that should be ideally consumed in an hour?
    For adults, their kidneys are capable of excreting about 0.7 to 1 liter water every hour, so that’s the amount one can drink. Ideally, one must not drink above 1.4 liters water in an hour.
  • How much water should be consumed in 1 day?
    On average, a healthy person who presumably consumes healthy food which has usual salt contents can drink about 11 liters water per day, if required. If a healthy person does not eat enough, or little, usually while starving or fasting, they do consume enough amount of salt, which is why they should drink about 5 liters water in a day.
  • How is overhydration different from hyperhydration?
    To put it simply, hyperhydration is opposite of dehydration and is used when there is excessive water amount in body. A person with this condition can have body swelling (edema, edema of ascites or abdominal cavity, and edema of legs). There may or may not be a presence of hyponatremia. Overhydration refers to drinking huge amounts of water in short spans of time leading to hyponatremia and water intoxication. If a person has this condition, they can become hyperhydrated or normally hydrated or can remain dehydrated (if they were dehydrated at the beginning of becoming hyperhydrated). For instance, if a dehydrated person has run a marathon and they drink lots of plain water, they can still be dehydrated, but they might already have hyponatremia because of overhydration.
  • What are the advantages of excessive amount of water?
    There aren’t any. Drinking massive amount of water, more than the body needs is not proven to help the prevention of kidney stone formation for people with family or personal history for kidney stones.

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