Sodium levels – the facts

Have you ever wondered if your sodium levels are normal? How high or low should they be?

Sodium levels in our blood are naturally balanced by our bodies. The normal range for sodium level is between 135 and 145 millimoles per litre (mmol/L), however some people have slightly higher sodium levels at around 146 to 148 mmol/L.

Having a low level of sodium in the blood (hyponatremia) is relatively common but a high level (hypernatremia) in the blood is much less so.

Here is a recent question put to the Health at Hand nurses:

I just had a blood test for arthritis and it showed a raised level of sodium. My GP has requested a further blood test but what does this mean?

“If you are generally feeling healthy then it is quite possible that the result was due to an error with the processing of your sample and a further test will show your sodium level to be normal. If you do have hypernatremia (a level of above 146 mmol/L) then you would be experiencing some of the following symptoms and further investigation will be needed.”

Hypernatremia causes and symptoms

The most common causes of hypernatremia (high sodium levels in the blood) are as a result of:

  • problems with your kidneys
  • dehydration – either from bouts of diarrhoea and vomiting or from the use of diuretics (tablets given for high blood pressure)
  • diabetes insipidus – this is a rare condition which affects the way the body processes water

The most common symptoms of hypernatremia may include:

  • feeling thirsty
  • nausea and vomiting
  • headaches
  • feeling confused
  • feeling lethargic
  • seizures
  • losing consciousness

 Hyponatremia causes and symptoms

The most common cause of hyponatremia (low sodium levels in the blood) is drinking too much water within a short space of time.

Most commonly the symptoms of hyponatremia include:

  • nausea and/or vomiting
  • headaches

In rare, serious cases, hyponatremia can cause swelling of the brain which can lead to confusion, seizures, coma and even death.

Ways to treat hypernatremia (high sodium levels in the blood) 

The 3 main ways of reducing sodium levels are to:

  • stay hydrated
  • reduce your salt intake
  • exercise

Read more on staying hydrated, diet and exercise and on reducing your salt intake

You could also take a look at our Healthy lifestyle pages for more information.

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Have you got a health question?

We've teamed up with AXA PPP healthcare to bring you articles, information and tips from their clinical teams on a wide range of health topics. And if you have a health related question of your own - about your or your family's health, medication or upcoming procedures, for example - you can also access their, "Ask the Expert" service. Available around the clock, 365 days a year this free resource allows you to ask the team of friendly and experienced nurses, midwives and pharmacists about any health concerns you may have - whenever you need them, 24 hours a day, every day. Please get in touch now.

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