Thought this was interesting.


Drinking too much water can kill you
http://www.azcentral.com/news/articles/0627dangers27.html
Carla McClain
Arizona Daily Star
Jun. 27, 2005 12:00 AM

TUCSON - Sometime in the middle of the night, Carol Tufts began to feel very strange. Dizzy, confused, disoriented.

By midmorning, she had collapsed into a chair, unable to walk, unaware of what day it was. She was, in fact, dying.

The reason? She drank too much water.

Too much water? In the southern Arizona desert? Where the never-ending mantra drummed into our heads tells us to drink water constantly to ward off the perils of our dry heat?

Well, Tufts followed that advice for years, drinking lots of water daily, to stay hydrated and healthy. And it almost killed her.

"This was a tremendous surprise to me. It's a fascinating phenomenon," said Tufts, 80, a longtime Tucson resident and mother of the late Randy Tufts, co-discoverer of Kartchner Caverns.

"I just think people really need to know there is such a thing as drinking too much water - even here - and that it can be very dangerous. I think there were warning signs this was happening to me, but I had no idea what they meant."

Her warning is timely, coming on the heels of a major medical study of endurance athletes that found drinking too much water during heavy, prolonged exercise may be an even greater threat than drinking too little.

In fact, that phenomenon has unexpectedly developed into one of the most common health threats to Grand Canyon hikers, where nearly a fifth were ending up as "water intoxication" emergencies until warnings were posted.

This year, the once-unrecognized problem made medical headlines after a study showed more than 10 percent of runners in the 2002 Boston Marathon finished the race with below-normal sodium levels, a condition called hyponatremia.

The reason? They drank too much water during the hours they were running, so much that they flushed sodium from their bodies, dangerously upsetting their electrolyte balance. When that happens, water enters the body's cells, which then swell. If swollen brain cells start pressing against the skull, the result is brain damage, paralysis, coma and sometimes death.

"We observed that hyponatremia occurs in a substantial fraction of marathon runners and can be severe," the authors of the study, published in the New England Journal of Medicine in April, concluded. "(It) has emerged as an important cause of race-related death and life-threatening illness among marathon runners."

Hyponatremia did in fact kill one runner that year: a 28-year old woman who was struggling badly the last six miles. Suffering nausea, fatigue and muscle weakness - symptoms similar to dehydration - she assumed that was the problem, chugged 16 more ounces of fluids, then collapsed and died.

Her blood sodium levels had plunged to 113 millimoles per liter of blood. Hyponatremia begins to occur at sodium levels below 135 and becomes life-threatening at about 120.

When Carol Tufts got to Tucson Medical Center the day she collapsed recently, her sodium level had plunged to 122.

"She was zoned, completely out of it. She was on her way down," said Tufts' daughter, Judy Rodin, who found her mother that morning during a routine stop and called 911.

Obviously, at 80, Carol Tufts was no marathon runner or Grand Canyon hiker. But she faithfully drank about 10 glasses of water a day, practicing what she thought was a good habit. That morning, when she felt so bad, she downed four glasses of water quickly, thinking hydration would help what felt like an irregular heartbeat. Tufts was also on medication for hypertension and osteoporosis, and also suffered mild hypothyroidism - a condition that can exacerbate sodium loss.

"We see this frequently, especially in elderly people. The cause usually is all the water they're drinking, combined with the medications they may be taking," said Dr. Ramakrishnan Subbureddiar, a geriatric specialist who treated Tufts during her rehabilitation.