What is Sodium?
Sodium is the primary electrolyte in blood and fluids outside cells. It regulates fluid balance, blood pressure, and nerve and muscle function.
Sodium is tightly regulated by the kidneys and hormones (ADH, aldosterone). The kidneys can adjust sodium excretion dramatically based on intake and fluid status. The normal range is narrow because small deviations can significantly affect brain and nerve function.
Why might Sodium be low?
Low sodium (hyponatremia) is the most common electrolyte abnormality. Causes include overhydration, diuretics, kidney or heart conditions, and certain hormonal disorders. Mild hyponatremia may be asymptomatic; severe cases can cause symptoms.
This information is educational. A single out-of-range result is rarely the whole picture — a healthcare professional can interpret your numbers alongside your overall health and history.
Context questions that matter
- →Was this result slightly or clearly outside the reference range?
- →Were related markers also high or low?
- →Is this new compared with previous tests?
- →Could recent illness, exercise, fasting, alcohol, supplements, or medication affect it?
- →Do you have symptoms that should be discussed with a clinician?
Markers often reviewed together with Sodium
Clinicians rarely look at one number in isolation. These markers usually accompany Sodium on a electrolytes panel and help put the result in context.
Lifestyle considerations
- •Staying adequately hydrated (but not over-hydrated) is the key for most people
- •Athletes performing long-endurance events need to balance water and electrolyte intake carefully
Questions to ask your doctor
- →Could hydration, kidney function, medication, diuretics, vomiting, diarrhea or supplements affect this low Sodium result?
- →Are the other electrolytes on this panel also high or low?
- →Should this be rechecked alongside kidney markers and acid–base context if relevant?
Don't guess from one flagged result.
Start with the most relevant panel and see how your markers fit together in plain English.
Frequently asked questions
What does low Sodium mean?
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Low sodium (hyponatremia) is the most common electrolyte abnormality. Causes include overhydration, diuretics, kidney or heart conditions, and certain hormonal disorders. Mild hyponatremia may be asymptomatic; severe cases can cause symptoms.
What is Sodium?
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Sodium is the primary electrolyte in blood and fluids outside cells. It regulates fluid balance, blood pressure, and nerve and muscle function.
Can hydration or medication affect electrolytes?
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Yes. Hydration status, kidney function, diuretics, vomiting, diarrhea and certain supplements can all shift electrolyte results. A single value is read together with your fluid status and any recent illness.
Should electrolytes be compared with kidney markers?
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Often yes. Sodium, potassium, chloride, bicarbonate and calcium are usually read alongside creatinine and eGFR — the kidneys regulate electrolyte balance, so the two systems are interpreted together.
What supports healthy Sodium levels?
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Staying adequately hydrated (but not over-hydrated) is the key for most people. Athletes performing long-endurance events need to balance water and electrolyte intake carefully