Sodium (Na): normal range & what your result means

Sodium is the main electrolyte controlling your body’s water balance. Both high and low levels can affect the brain.

Typical adult reference range

Measure	Range
Normal	135–145 mmol/L
Low (hyponatraemia)	< 135 mmol/L
High (hypernatraemia)	> 145 mmol/L

What a HIGH result can mean

High sodium usually means dehydration (not enough water)

What a LOW result can mean

Low sodium can cause nausea, headache and confusion; causes include diuretics, excess water and hormonal problems

Ranges vary by lab. Reference ranges are TYPICAL ADULT values and vary by laboratory, age, sex, pregnancy and the method used. Always read your result against the range printed on YOUR report, and let your doctor interpret it alongside your history.

Frequently asked questions

What are the symptoms of low sodium?

Mild cases may cause none; lower levels bring nausea, headache, confusion and, if severe, seizures. The cause must be found before correcting it, which is done carefully.

Can drinking too much water lower sodium?

Yes — drinking excessive water quickly can dilute blood sodium. It is uncommon but can be serious in endurance athletes or certain conditions.

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MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.