Water – How Much is Too Much?

A few years ago, my friend encouraged her father to drink large amounts of water through hot and sultry summer afternoons in India in a bid to sustain hydration in him — with solely good intentions. The next year, he was diagnosed with cardiomyopathy — which meant that his heart muscles were not pumping efficiently; leading to water retention and dilation of the heart. While the water drinking of the previous year did not cause the heart failure, co-existence of both events could have had a devastating effect on his health. Unfortunately, a woman from Sacramento, CA was not as lucky, and died as a result of consuming too much water. She voluntarily consumed about 8 ounces every 15 minutes for a whole day while controlling her bladder.

Water intoxication is a medical condition where the body is overhydrated, caused by consuming excessively large amounts of water. Water intoxication is also dependent on the rate of consumption of the water. When the body gets too much water too quickly, body fluids become to dilute, leading to electrolyte and mineral imbalances. The concentration of sodium, one of the most essential elements, especially decreases leading to hyponatremia. The water in the cells become too dilute due to which osmosis occurs, leading to an influx of water from the outside of the cells to the inside. When this happens, in theory cells might swell to the point of rupturing the cell walls. Other effects of water intoxication include water entering the lungs, pressure on the nerves and spinal cord, and swelling of the brain. Symptoms include mental confusion, fatigue, slurred speech, seizures and death.

This condition is mostly reported in athletes and babies. When athletes train for or run long marathons, they sweat, losing a lot of water. In addition to water, electrolytes are also eliminated via sweat. When athletes attempt to replenish this by consuming plain water, they are in theory further diluting their precious reserve of the salts in the body. To avoid this, experts recommend that they drink sport drinks that contain minerals and essential salts, and also consume foods high in salts during or after a very long run. Babies have low body mass as compared with adults, and so they require significantly less water than adults. They may suffer from water intoxication if they are given large quantities of extra-dilute formula or if they are given too many bottles in one day. People consuming certain psychiatric medications, or people who are on a liquid diet should also balance their fluid consumption and excretion with care.

If overhydration does occur, it may be reversed through:

  • Diuretics, which increase the rate of urination, thereby concentrating the blood
  • Intravenous infusion of saline solution
  • Other forms of palliative care and pharmacological intervention by medical professionals

Water intoxication is very rare and requires very specific sets of circumstances to build up. But it can occur. The general guidelines are to drink about 8-12 eight ounce glasses of water a day, unless one is in very dry weather, exercising, or taking certain medications affecting the heart and kidneys. Staying within these ranges will usually nourish the body without causing an overload on the cardiac and renal systems.


Irene Baldoni, Rosanna Cordiali, Mauro Jorini, Mohamad Maghnie, Fernando M. de Benedictis (2007). Case 1: An infant with water intoxication. Acta Paediatrica, 96 (6), 926-927 DOI: 10.1111/j.1651-2227.2007.00312.x

Nirupama Shankar, PT, MHS

Nirupama Shankar, PT, MHS, is a physical therapist by profession, and has over 7 years of clinical experience in the field of neurological rehabilitation. She has treated individuals with stroke, traumatic brain injury, spinal cord injury, Parkinson's disease, multiple sclerosis, and amputations. She has also completed training modules and community education projects in Michigan and North Carolina.
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