While excess sodium in your diet can lead to harmful effects, too little sodium can be dangerous as well. This is because your body uses sodium to perform a variety of functions, ranging from maintaining your fluid levels to keeping your heart beating. Understanding what can cause low blood sodium, and how it affects you if you experience it, can help you avoid this life-threatening occurrence.
Significance
Low blood sodium is called hyponatremia. Sodium is the most abundant electrolyte found outside your cells. When you don't have enough sodium outside your cells, the fluid in your body becomes attracted to the electrolytes inside your cells. Imagine your cells like a balloon filling with air -- ultimately, when too much water enters the cells, they can burst. Normal sodium levels range from 135 to 145 mEq/L. If your level dips below 125 mEq/L, it is considered a severely low blood sodium level. Your physician can test your sodium levels with a blood or urine test.
Symptoms
Low blood sodium levels may first start to affect you with moderate symptoms. You may experience feelings of nausea, headache, confusion, lethargy, fatigue, loss of appetite or feelings of restlessness. Experiencing these symptoms can indicate the need to seek medical treatment. If your low blood sodium levels continue, your symptoms can progress to include muscle weakness, muscle spasms, seizures and loss of consciousness that can lead to coma. This is a medical emergency, and you should seek immediate medical treatment if it occurs.
Causes
Low blood sodium levels can be a concern both for their immediate symptoms and because they can indicate an underlying medical condition. An underactive thyroid, kidney problems, cirrhosis of the liver and congestive heart failure can all lead to hyponatremia. However, vomiting and/or diarrhea can also cause low blood sodium. Additionally, certain medications, including diuretics or antidepressants, are linked with low blood sodium levels. Marathon runners also commonly experience low blood sodium levels because they lose sodium when sweating. Drinking too much water also can saturate the blood, resulting in more fluid than sodium.
Solution
Severely low blood sodium levels should be treated in an emergency health care setting. Your physician will likely begin an intravenous, or IV, fluid drip of a sodium-containing solution. He will also evaluate your overall health and medications you take to determine the underlying cause of your low blood sodium. Some instances, such as kidney disease, may necessitate fluid restriction to ensure you are not taking in more fluid than your body can process.
