The Importance of Sodium while you run(Esp. if you are runni

Hyponatremia
Dilutional hyponatremia; Euvolemic hyponatremia; Hypervolemic hyponatremia; Hypovolemic hyponatremia
Last reviewed: May 29, 2011.

Hyponatremia is a metabolic condition in which there is not enough sodium (salt) in the body fluids outside the cells.

Causes, incidence, and risk factors
Sodium is found mostly in the body fluids outside the cells. It is very important for maintaining blood pressure. Sodium is also needed for nerves and muscles to work properly.

When the amount of sodium in fluids outside cells drops, water moves into the cells to balance the levels. This causes the cells to swell with too much water. Although most cells can handle this swelling, brain cells cannot, because the skull bones confine them. Brain swelling causes most of the symptoms of hyponatremia.

In hyponatremia, the imbalance of water to salt is caused by one of three conditions:

Euvolemic hyponatremia -- total body water increases, but the body's sodium content stays the same

Hypervolemic hyponatremia -- both sodium and water content in the body increase, but the water gain is greater

Hypovolemic hyponatremia -- water and sodium are both lost from the body, but the sodium loss is greater

Hyponatremia is the most common electrolyte disorder in the United States.

Causes of hyponatremia include:

Burns

Congestive heart failure

Diarrhea

Diuretic medications, which increase urine output

Kidney diseases

Liver cirrhosis

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Sweating

Vomiting

Symptoms
Common symptoms include:

Abnormal mental status

Confusion

Decreased consciousness

Hallucinations

Possible coma


Convulsions

Fatigue

Headache

Irritability

Loss of appetite

Muscle spasms or cramps

Muscle weakness

Nausea

Restlessness

Vomiting