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What is Sodium Deficiency?

By Amy Hunter
Updated: May 17, 2024

Sodium deficiency, or hyponatremia, is a term used when the body's balance of electrolytes becomes unstable. There may be too much fluid in the system, diluting the sodium, or the sodium levels themselves may be too low. While this condition can occur on its own, it can also develop because of excessive diarrhea or vomiting. Another way that it can develop is when someone experiences excessive fluid buildup, or edema, when the body cannot expel the excess water as quickly as it builds up.

Someone experiencing a mild case of sodium deficiency may not exhibit any symptoms. More advanced cases may lead to fatigue, nausea, and vomiting. If a person experiencing this condition begins vomiting, the disease accelerates much quicker, due to the electrolyte imbalances that occur when sick. In severe cases of sodium deficiency, the symptoms are mostly neurological. They include confusion, the loss of reflexive movement, convulsions, and, eventually, a coma.

The treatment for sodium deficiency includes water restriction, intravenous saline, and the administration of diuretics. It is important that someone receiving treatment for this illness receives careful monitoring, because excessively rapid stabilization can lead to heart failure. If the patient develops sodium deficiency because of another health condition, such as food poisoning, that led to excessive vomiting and diarrhea, physicians will treat the initial illness as well.

Sodium deficiency is sometimes called water intoxication. In some cases, athletes, particularly distance athletes, develop water intoxication while competing. It is most common in marathon runners. The runner, in his or her quest to remain hydrated, drinks so much water that the levels of sodium in the blood are diluted.

To avoid the risk of water intoxication, athletes can alternate drinking water with sports drinks while running, or use sports gels or other electrolyte replacement supplements. It is important to try the electrolyte supplementation products you plan to use before race day. Many people drink one particular brand of supplement during their training runs.

A different brand of sports drink on race day can lead to an upset stomach. The runner then often switches to drinking only water to avoid the discomfort, increasing the risk of developing hyponatremia. If the sports drink the race is serving does not agree with you, pack some sports gels so that you can safely stick with water through the race.

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Discussion Comments
By discographer — On Oct 13, 2013

I experience symptoms of sodium deficiency during summer. I work outdoors and sometimes, due to the heat and loss of sodium, my blood pressure falls. I get dizzy, tired and cannot work. My doctor had me get a blood test and said that my sodium is in the low range. For some reason, it doesn't affect me as much in cold weather though.

By burcidi — On Oct 12, 2013

@anamur-- Sodium deficiency in blood is not common but some groups are more likely to experience it, like athletes as the article mentioned.

We do get plenty of salt through our diet but there may be circumstances where this salt leaves the body very quickly. For example, when someone is very active and constantly sweating and drinking water for re-hydration, sodium deficiency is possible. We lose a lot of salt through sweat and the more water we drink, the more diluted the salt in the body become.

This is why athletes are recommended to drink electrolyte water and eat or drink something salty during intense exercises.

The same thing can happen if you lose a lot of water very quickly, such as through vomiting and diarrhea. Sodium leaves the body along with water.

By serenesurface — On Oct 11, 2013

I'm surprised that a deficiency of sodium is possible nowadays, considering that most of what we buy from the grocery has excessive salt.

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