Minerals take charge of key body actions
Aug. 2, 2005 12:00 AM
Dehydration and electrolyte imbalances can go hand-in-hand, sometimes causing life-threatening heart arrhythmias, seizures or other problems, says emergency-room physician Frank LoVecchio of Banner Good Samaritan Medical Center in Phoenix.
What are electrolytes?
Electrolytes, found naturally in your blood and other body fluids, are minerals that carry an electrical charge. They keep fluids properly balanced by moving them from blood to tissues and back, and they carry nerve impulses, helping to maintain normal body functions such as heart rhythm, muscle contraction and brain function. Sodium and potassium usually are the most critical electrolytes.
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Sodium's role
Sodium is the major electrolyte in body fluids. It helps maintain the right amount of water inside and outside the cells and in your blood, and it aids in the transmission of electrical signals in the brain and muscles.
• If sodium is too low: Sweating, diarrhea or vomiting can deplete the body of sodium-rich fluid. Or excessive water intake can dilute sodium outside the cells, a condition known as hyponatremia. Water then moves into the cells, making them swell, even in the brain, resulting in muscle cramps, headache, weakness, lethargy, seizures, coma or death.
• If sodium is too high: Dehydration can cause water loss that is disproportionately greater than sodium loss. When sodium is too highly concentrated in the body, a condition called hypernatremia, water moves out of cells and into the blood, and the brain can shrink. Symptoms resemble low sodium's.
Potassium's role
Potassium is the major electrolyte inside the cells. Along with sodium, potassium's passage in and out of cells helps regulate the balance of body fluids and the transmission of nerve impulses. If potassium levels are too low or too high, for reasons similar to those affecting sodium levels, abnormal heart rhythms and muscle weakness can develop.
Can you overdo water?
Not usually in hot weather, but it happens. At the Grand Canyon, hikers sometimes suffer from "water intoxication," or hyponatremia, when excessive fluid intake flushes sodium from their body.
How much water is recommended?
Recommendations vary depending on your weight, activity level and overall health, but drinking eight to 10 8-ounce glasses of water (64 to 80 ounces) daily is the generally accepted minimum.
Do sports drinks help?
Exercise science specialist Jeff Messer of Mesa Community College recommends sports drinks after exertion to replace electrolytes and keep levels constant. Sugar- and water-based, the drinks also are a good source of carbohydrates and fluid, especially for people exercising for an hour or more or spending a lot of time outside.
Water "turns off" the thirst mechanism before you're completely rehydrated, while electrolytes increase a drink's palatability, encouraging you to drink more, says LoVecchio of Banner Good Samaritan.
A suggestion
If you're worried about consuming too much sugar or overdoing the electrolytes, try mixing 1 part sports drink to 2 parts water. Talk with your doctor about what's safe in your circumstances.
- Connie Midey
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