Water can be harmful in excess

Thursday, July 28, 2011

Everything is good in moderation, even water, but too much of anything can be harmful to the human body -- even water.

While area residents struggle to find ways to stay cool during these triple-digit temperatures, water is one of the first things that comes to mind. A tall glass of ice water after mowing the yard. Splashing around in a cool pool or at the lake with friends. A running hose to douse a hot body after a sporting event. In fact, blood is made up of about 92 percent water.

But the danger lies in an individual drinking too much water for their body mass, thus flushing out vital sodium and electrolytes, sending the body into a dangerous, and potentially fatal, imbalance.

"Water can be poisonous when a person drinks too much of it," said David Compton, director of the Barry County Office of Emergency Management. "People who work outdoors during intense heat, or those who participate in endurance sports, are most likely to suffer from water poisoning or water intoxication. People who have medical issues, who are taking certain kinds of medications and infants are also susceptible to water poisoning."

When water poisoning occurs, fluid outside the blood cells that are depleted of sodium and electrolytes through sweating, severe diarrhea and vomiting, those using certain drugs, such as Ecstasy, or those undergoing diuretic therapy. That fluid shifts into the blood cells in an effort to balance the body's concentration, causing those cells to swell.

In the brain, this swelling increases pressure on the brain, leading to headaches, personality changes, changes in behavior, confusion, irritability and drowsiness.

Other signs of water intoxication include difficulty in breathing during exertion, muscle weakness, cramping, nausea or vomiting.

Eventually, cells in the brain may swell to the point where pressure is applied to the brain stem, which controls vital life functions such as breathing, heartbeat, and blood pressure, causing that system to shut down.

"Water is a good way to rehydrate," Compton said, "but they have to replace those lost electrolytes to keep their systems balanced."

Beverages that replace lost electrolytes, sodium, potassium and chloride include Gatorade, Propel Fitness Water, and PowerBar Endurance, among others.

"A person's water intake should not exceed one to two liters a day, depending on their body mass," Compton said. "While it's necessary to replace body fluids lost through exertion or illness, it should be done with reasonable care.

"Too much of a good thing is still too much, and the consequences could be life-threatening," Compton said.

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