Drinking too much water can cause the level of sodium in the blood to fall abnormally low.
Sodium is vital for regulating the amount of water in the body and controlling blood pressure, nerves and muscles.
Too little of the electrolyte, medically known as hyponatraemia, causes a build-up of water in and around the body’s cells.
This causes cells to swell and can trigger symptoms that range from mild to life-threatening, such as headaches, vomiting and seizures.
The normal blood sodium level is 135 to 145 milliequivalents per litre (mEq/L). Hyponatraemia occurs when the level falls below 135 mEq/L.
Doctors believe Kung fu legend Bruce Lee may have died from the condition, while English actor Anthony Andrews has told how he was hospitalised due to hyponatraemia.
Fatalities and hospital admissions have been reported after people drank seven to eight litres of water — compared to the daily recommendation of around two litres.
What causes hyponatraemia?
Causes of hyponatraemia include:
- Excessive thirst – Causes too much fluid intake
- Kidney failure – The kidneys cannot rid the body of excess fluid
- Congestive heart failure – Excess fluid builds up in the body
- Diuretics (water pills) – Makes the body get rid of more sodium in the urine
- Severe vomiting or diarrhoea – The body loses a lot of fluid and sodium
- Antidepressants and pain medication – May cause more sweating and urinating than normal
What are the symptoms of hyponatraemia?
Symptoms of hyponatraemia include:
- Nausea or vomiting
- Low blood pressure
- Loss of energy
- Muscle weakness, twitching or cramps
- Restlessness or a bad temper
- Headache, confusion or fatigue
- Seizures or coma
How is hyponatraemia treated?
Treatment for hyponatraemia varies on the severity but the first step may be to cut back the amount of liquids you drink or adjust your diuretic (water pill) usage.
Your GP may also recommend an IV drip of sodium solution, prescribe sodium retaining medicines or dialysis.
