Sodium: normal range and what it means
A tightly controlled electrolyte for fluid balance.
Normal range
Adult reference range.
- Low< 135 mmol/L
- Normal135 – 145 mmol/L
- High≥ 145 mmol/L
What it measures
The main electrolyte outside your cells, and the one that sets your body’s water balance. It is held in a very tight range, so even small deviations are meaningful.
What moves it
Water balance far more than salt intake. It reflects how dilute or concentrated your blood is, so fluid intake, sweating and some medications move it.
How to bring it into range
Abnormal results are usually about water rather than salt intake, and are a medical question rather than a dietary one.
How fast it responds
Hours to days.
Also reported as: na · serum sodium
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Common questions
- What is a normal Sodium level?
- Normal: 135 – 145 mmol/L. Adult reference range.
- What does a high Sodium mean?
- A value above the reference band means Sodium is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my Sodium?
- Abnormal results are usually about water rather than salt intake, and are a medical question rather than a dietary one.
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Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.