Water Toxicity: What Amount Of Water Intake Can Become Fatal

Drinking too much water can prove fatal. Sounds shocking, but it is true. A 35-year-old mother from Indiana, US, recently succumbed to water intoxication. Reportedly, she and her family were out at Lake Freeman over the Fourth of July weekend when she began feeling severely dehydrated. The woman died after consuming an estimated 64 ounces of water, about 1.8 litres (what you're supposed to drink in a whole day) in just 20 minutes. 

Speaking with the OnlyMyHealth team, Dr Pankaj Verma, Senior Consultant-Internal Medicine, Narayana Superspeciality Hospital, Gurugram, explains what water toxicity is, why it happens, and how much water intake is normal.

What Is Water Toxicity?

“Water toxicity occurs when the body takes in an excessive amount of water, overwhelming its ability to eliminate it,” says Dr Verma, adding, “This leads to an imbalance in electrolytes, mainly sodium, which is essential for the normal functioning of cells.”

When sodium levels fall too low, lower than 135 millimoles per litre (mmol/l), it can cause a condition called hyponatremia. 

A study published in the British Medical Journal (BMJ) found an association between excessive water intake and life-threatening hyponatremia, which the study authors call rare. 

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"The median volume of water consumed and serum sodium at presentation was 8 L/day and 118 mmol/L, respectively. The motivator for increased water consumption was psychogenic polydipsia at 55%, iatrogenic at 13%, exercise at 12%, habitual/dipsogenic polydipsia at 7%, and other reasons at 13%," says the study, adding that it caused severe complication (seizures and coma) in 53% of the participants, moderate symptoms in 35% (confusion, vomiting, agitation) and mild issues in 5% (dizziness, lethargy, cognitive deficit).

Signs You Shouldn’t Ignore

Signs of water toxicity include:

• Nausea
• Headache 
• Lightheadedness and confusion
• Seizures
• Coma 

According to Dr Verma, it can be life-threatening in severe cases, which is why it is crucial to recognise these symptoms and seek immediate medical attention if they occur, especially if there has been excessive water intake.

Can Water Intoxication Be Fatal?

Reports of individuals dying due to water intoxication only confirm that drinking too much water can be fatal. 

According to a study published in the Journal of Clinical Pathology, water intoxication needs to be addressed at an early stage as it can lead to seizures, coma, and death, if left untreated. 

The study shares a case study of a 64-year-old woman with a known history of mitral valve disease but no other relevant past history. 

"On the evening before her death, she began compulsively drinking water in vast quantities, estimated at between 30 and 40 glasses, and this was interspersed with episodes of vomiting. She became hysterical and also distressed, shouting that she had not drunk enough water. She declined medical attention but continued to drink water after she had gone to bed. She later fell asleep and died some time later," the case study read. 

The postmortem examination stated the cause of death as hyponatraemia as a result of acute water intoxication.

Also Read: Experiencing Diarrhoea And Other Digestive Issues? It Could Be SIBO; Know What It Is

How Much Water Is Too Much?

Dr Verma says, “While the amount of water intake that can become fatal varies depending on individual factors, such as weight, health condition, and activity level, it is generally accepted that consuming an extremely large quantity of water within a short period can be dangerous.”

“On the other hand, determining the ideal water intake for an individual can be a bit complex and depends on several factors. However, a general recommendation is to drink at least 9 glasses of water per day, but this can vary based on factors like climate, physical activity, and overall health. It is always important to listen to your body's signals and adjust your water intake accordingly,” he adds. 

A 2013 study reported that the kidneys can remove about 20–28 litres of water a day, which means no more than 0.8-1.0 litres every hour. Therefore, anything above that can be harmful.

The Final Word

Staying hydrated is important and choosing water as your go-to drink is beneficial. But going overboard with your water consumption can do more harm than good. While you must listen to your body’s demand for water, it is also crucial that you address any signs of severe dehydration, even after drinking water. Speak to a healthcare provider to avoid water intoxication and complications associated with it.