Sodium
Sodium is a salt in the blood that helps control fluid balance and lets nerves and muscles work.
Sodium is a salt in the blood that helps control fluid balance and lets nerves and muscles work. The kidneys keep the level within a narrow band by holding on to or letting go of sodium and water. The value mostly reflects the balance between salt and water in the body. Retesting shows how it changes over time.
Fluid intake matters most: drinking very large amounts of water lowers sodium, and too little fluid or heavy sweating raises it. Vomiting, diarrhoea, long endurance exercise and some medicines, such as diuretics, also affect the level.
Foods that help
A varied diet with vegetables, fruit and home-cooked food, and drinking to thirst. During long exercise in heat, sports drinks with salt can help replace what is lost in sweat.
Foods to limit
A lot of very salty food (processed meat, crisps, ready meals). Very large amounts of plain water over a short time.
Track it through the year
One value is a snapshot. Following it up shows whether what you changed is working.
Related markers
Educational information only — not a diagnosis. Every result is checked against safe limits, and anything critical is escalated for follow-up.
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