What is the normal serum sodium concentration?
Sep 23, 2025
Source: Cainiu Health
Dr. Liu Feng
Introduction
Under normal circumstances, the normal serum sodium concentration range is 135–145 mmol/L. In daily life, it is important to promptly replenish fluids and electrolytes after excessive sweating, vomiting, or diarrhea to prevent abnormal serum sodium levels. If symptoms such as fatigue, dizziness, or nausea occur, medical attention should be sought promptly to check serum sodium levels. Additionally, maintaining a balanced diet is essential.
Under normal circumstances, the normal serum sodium concentration range is 135–145 mmol/L. Detailed explanation is as follows:
The normal serum sodium concentration range is a key indicator for maintaining stable physiological functions in the human body. The osmotic pressure balance between intracellular and extracellular fluids depends on stable serum sodium levels; deviations from the normal range can cause cells to either absorb or lose water, thereby affecting cellular metabolism and function. Meanwhile, serum sodium plays a role in regulating fluid distribution, ensuring normal blood circulation volume and providing the basis for adequate blood and oxygen supply to organs. It also supports nerve impulse conduction and muscle contraction, ensuring proper functioning of the nervous and musculoskeletal systems. Therefore, serum sodium levels must be maintained within the 135–145 mmol/L range.
In daily life, it's important to promptly replenish fluids and electrolytes after excessive sweating, vomiting, or diarrhea to prevent abnormal serum sodium levels. If symptoms such as fatigue, dizziness, or nausea occur, medical evaluation of serum sodium levels should be sought promptly. Additionally, a balanced diet is essential—avoid long-term excessive intake of high-salt foods or overly restrictive sodium consumption—to maintain stable serum sodium concentrations.
