What sodium level is considered low sodium?

A sodium level lower than 135 milliequivalents per liter (mEq/L) is considered low sodium, a condition known as hyponatremia. This condition can lead to various symptoms, including confusion, headache, and in severe cases, seizures or coma. It's essential to monitor sodium levels, especially in individuals who may be at risk, such as those with certain medical conditions or on specific medications.