Water intoxication

What is water intoxication?

Water intoxication means a drop of blood sodium bellow 130 mmol/liter (hyponatremia) as a result of excessive water intake ^[1]. Water intoxication can occur when you consume too much water and too little salt in a short time.

People have died after drinking, for example, 3-4 liters of water in few hours (a woman, 40 years; 2 girls, 3 and 4 years) ^[5,6,7], 6 liters in few hours (a girl, 12 years) ^[8] or 3 gallons, that is 11 liters, probably within few hours (a 25 years old man after a bike ride) ^[9].

Causes and Risk Factors

• “Water fasting,” “water only diet” or “detox diet” as a weight loss method
• Water drinking contests
• Drinking large amounts of beer without eating (beer potomania)
• Psychological disorders with excessive thirst (psychogenic polydipsia)
• Marathon or triathlon running, cycling or hard physical work, lasting for more than 5 hours, in a hot climate in combination with excessive drinking and insufficient sodium intake; slow, small women marathon runners who drink more than they sweat seem to be at greatest risk ^[11].
• Aspirin, ibuprofen or other nonsteroidal anti-inflammatory drugs (NSAIDs) may stimulate sodium loss through the kidneys and thus increase the risk of hyponatremia in athletes ^[10].
• Disorders with low blood sodium levels (hyponatremia): advanced kidney failure, adrenal insufficiency, congestive heart failure, syndrome of inappropriate ADH secretion (SIADH), thiazide diuretics
• In infants: feeding an infant with formula diluted with water. Several cases of seizures ^[13,14] and even death from water intoxication in infants after consuming diluted formula were reported.

Symptoms

Symptoms may include headache, weakness, nausea or vomiting, swollen hands and feet and, in severe cases, muscle cramps, wheezy breathing (due to pulmonary edema), confusion, seizures, coma or death (due to brain swelling ─ cerebral edema) ^[1].

The main sign of water intoxication is a sudden weight gain, and sometimes, swelling of the feet. Water intoxication can occur without weight gain and even with moderate weight loss due to dehydration ^[1].

Diagnosis. In water intoxication, blood sodium levels are decreased ^[3].

Treatment of water intoxication may include infusion of hypertonic saline, diuretics, steroids and other drugs ^[3].

Prevention. It is not likely you will suffer from water intoxication by drinking too much by accident in an everyday scenario. During marathon, you can avoid water intoxication by drinking only to thirst and regular sodium consumption from usual foods before the race. Note, that relatively low amount of sodium in commercial sport drinks, when drunk in excess, does not prevent water intoxication.