Water intoxication

Until recently people always stated that one could not drink too much water. Now, we know better. Just like any food stuff of beverage, water may negatively affect the body when drinking more than normal amounts. Water intoxication may occur at amounts of more than 3 litres and hour. You might think "No one drinks this much water". However, there are examples of situations where people did drink this much, or more.

In 2005 a student from The Netherlands was ordered to drink a whole glass of water during a hazing game, every time he got an answer wrong. Unfortunately, he did not know many of the required answers, and was intoxicated as a result. He first experienced an episode of epilepsy, and than lost consciousness. He was rushed to hospital, where he just barely survived.

Earlier, XTC-users died of water intoxication. Drug application leads to thirst, and consequently one might drink large amounts of water after a night out. However, XTC also causes the sodium concentration in the body to decrease (hyponatraemia), causing drinking and no additional feeding to have serious consequences. If one wants to safely drink large amounts of water, it is best to combine this with eating (salty) food. If one drinks too much, taking salt or sugar is recommended.

Long-distance runners and bikers are a risk category. They sweat and thereby lose large amounts of water at once. The water balance is restored by drinking large amounts of water during physical efforts. Many examples can be given of marathon runners that died from water intoxication. The risk is particularly high for this category, because people do not eat during running or biking. To prevent the consequences of water over saturation, long-distance bikers often eat large plates of spaghetti before a race. The American Athletics Association now has specific regulation for drinking during physical effort.

Mechanism

The mechanism of water intoxication is associated with osmotic pressure in cells. At decreasing amounts of salt in the blood, cells adjust by taking up more and more water. Consequently, the cells will swell. If this leads to transport of high amounts of water to the brain it may be extremely harmful. Swollen cells press the nerves, causing someone to experience headache. When cells seal blood vessels, this may cause a lack of oxygen, and someone loses consciousness. The direct cause of death by water intoxication is often brain oedema.

Sources

België.be
British Medial Journal, July 2003
Intermediair, 16-06-2005
NRC Handelsblad, 26-07-2003