Water intoxication is rare, and it is very difficult to consume too much water by accident. However, it can happen — there have been numerous medical reports of death due to excessive water intake.
Water intoxication most commonly affects people participating in sporting events or endurance training, or people who have various mental health conditions.
Sporting events
Water intoxication is particularly common among endurance athletes. It can happen if a person drinks a lot of water without correctly accounting for electrolyte losses.
For this reason, hyponatremia often occurs during major sporting events.
As the authors of
one study report, out of 488 participants in the 2002 Boston Marathon, 13% had hyponatremia symptoms, and 0.6% had critical hyponatremia, with sodium levels of less than 120 mmol/l.
Instances of water intoxication at these events have resulted in death.
One caseTrusted Source involved a runner who had collapsed after a marathon.
Because he was improperly rehydrated, his sodium levels fell below 130 mmol/l. The runner then developed water on the brain, known as
hydrocephalus, and a hernia in his brain stem, which caused his death.
Military training
One medical reportTrusted Source described 17 soldiers who developed hyponatremia after drinking too much water during training. Their blood sodium levels were 115–130 mmol/l, while the normal range is
135–145 mmol/l.
According to
another reportTrusted Source, three soldiers died due to hyponatremia and cerebral edema. These deaths were associated with drinking more than 5 liters of water in just a few hours.
The symptoms of hyponatremia can be misinterpreted as those of
dehydration. According to
one reportTrusted Source, a soldier who received an incorrect diagnosis of dehydration and heat stroke died from water intoxication as a result of rehydration efforts.
