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What Happens If You Drink Too Much Water?

Do you need to force yourself to drink eight or ten glasses of water a day, or could you be getting too much water?

Many people believe that drinking eight 8-ounce glasses of water a day is essential for good health. But do you really need that much? What happens if you drink too much water?

Can You Drink Too Much Water?

Australian researchers have conducted sophisticated studies and concluded that overdrinking may actually be hazardous to peoples’ health. The study demonstrated that people develop a natural reluctance to swallow when they have drunk too much water. The body has a very carefully regulated system for adjusting fluid intake, and forcing fluids runs up against that system.

The investigators used functional MRI imaging of the brain getting ready to swallow water under two different conditions. In one, the subjects had exercised and were thirsty; in the second, they had already drunk ample water and were asked to drink more.

Subjects rated the difficulty of swallowing three times higher when they were not thirsty. The brain scans showed excess activity in the pre-frontal cortex in this situation. In other words, the brain was attempting to bypass inhibition of the swallowing reflex.

Too Much Water Can Lead to Hyponatremia:

The authors note that overdrinking can lead to hyponatremia, a condition in which too little sodium is circulating throughout the body. This can become a life-threatening situation. The symptoms include nausea, headache, fatigue, confusion and muscle weakness or cramps. Continued hyponatremia or severe cases can result in seizures or coma. You can read a bit more about it here.

The Australian scientists who conducted the research note that thirst is usually the best guide for how much water to drink. There are two exceptions: very young children and the elderly. In those cases fluid intake may need to be monitored because thirst is less efficient. Dehydration can lead to serious complications just as hyponatremia can. Decreased urine output (fewer wet diapers in babies), more concentrated (darker) urine, headache, dry skin and dizziness or lightheadedness are possible symptoms of mild to moderate dehydration.

PNAS, October 10, 2016

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies..
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