Low blood sodium concentration is referred to as hyponatremia; it is dangerous because it may cause brain swelling, which may lead to seizures, comma or even death, explains BootsWebMD. Mild hyponatremia can cause nausea, vomiting, tiredness and muscle spasms or cramps.
Sodium helps maintain normal blood pressure, enhances nerve and muscle function and regulates body fluid balance, states MedlinePlus. When blood sodium concentration drops below normal, it triggers body cells to absorb water and swell. Swelling of brain cells confined in the skull causes increased pressure that may lead to seizures, comma or even death, according to Mayo Clinic.
Hyponatremia occurs when blood sodium falls below 135 milliequivalents per liter, or mEq/L, notes Mayo Clinic. This can be a result of diuretic medication; severe vomiting and diarrhea; or kidney, heart or liver disease. Drinking a lot of water during endurance activities can also cause low blood sodium levels.
The elderly are at higher risk of hyponatremia due to associated body changes like reduced kidney, liver and heart functions. People can prevent hyponatremia by drinking sports beverages during endurance events, drinking water in moderation and seeking treatment for conditions such as adrenal gland insufficiency, according to MedlinePlus. Treatments may involve IV fluids, medication and water restriction.