A low sodium in the blood is called hyponatraemia, and it is more common in older adults than many people think. The symptoms are vague: drowsiness, confusion, muscle weakness and sometimes falls. The cause often lies with medicines or with kidneys that work more slowly (Filippatos et al., 2017).
We notice that a low sodium is easily mistaken for ordinary ageing. That is exactly why it helps to know what the signals are.
Sodium is one of the most important salts in your body. Together with water it determines how much fluid sits in and around your cells. If that ratio drifts, your head often notices first. In older adults that happens sooner than in younger people.
What does a low sodium mean?
Sodium regulates the fluid balance in your body together with water. With a low sodium there is relatively too much water compared with salt. Your body normally keeps sodium neatly on level, so a low value is a sign that something is out of balance.
Thuisarts.nl describes that a slightly lowered sodium often gives no complaints, but that a stronger drop does become noticeable.
| Where you may notice it | Example |
|---|---|
| Head | Drowsiness, headache, confusion |
| Muscles | Weakness, cramp |
| Balance | Dizziness, greater risk of falling |
| Stomach | Nausea, less appetite |
These complaints are non-specific, so they do not point to sodium with certainty. They give a direction.
Why are older adults at extra risk of a low sodium?
With age the kidneys regulate the fluid and salt balance less tightly, and people more often use medicines that affect sodium. Well-known examples are certain water pills and some antidepressants (Filippatos et al., 2017). Drinking a lot on a warm day can also dilute the sodium.
The Dutch Farmacotherapeutisch Kompas names hyponatraemia as a possible side effect of diuretics and of SSRI antidepressants. Never stop these medicines yourself, but discuss concerns with your GP.
Do you use medicines that act on the kidneys? Then also read medication and your kidneys or the piece on potassium deficiency.
What does your sodium value in the blood mean?
Sodium is held within a fairly narrow range in your blood. A value below it is called hyponatraemia, a value above it hypernatraemia. Above all, how quickly the value drops determines whether you notice complaints.
You can have your sodium measured via the sodium blood value. A doctor registered in the Dutch BIG register reviews the result and places it in context.
Sodium is often looked at together with potassium and kidney function, because they influence each other.
What can you do yourself if in doubt?
Do you notice drowsiness, confusion or unexplained falls? Take that seriously and have it looked into calmly. Do not start drinking less or more on your own without discussion, because both can disturb the balance.
My advice: discuss complaints and your medicines with your GP. A blood test can support the conversation.
Want the bigger picture? Then read the pillar on vitamins and minerals after 60 or the piece on magnesium deficiency.
How is a low sodium investigated?
A low sodium is usually found with a blood test, often together with potassium and kidney function. Your GP also looks at your medicines, your fluid intake and any other conditions. That way the doctor tries to find the cause, because the cause determines the approach.
Sometimes the urine is checked too, to see how the kidneys handle salt and water. That helps to tell the different causes apart.
So it is not a matter of one number, but of the whole picture. That is why assessment by a doctor is important with a low value.
What can you keep an eye on yourself?
With a known risk, for example through water pills or antidepressants, it is good to be alert to drowsiness, confusion or falling more often. If your partner or carer notices that you react differently than usual, take that seriously.
Do not simply drink a lot of extra water on warm days without discussing it with your GP, certainly if you know your sodium can be low. Cutting salt without discussion is not always wise either.
My advice: keep an eye above all on changes in your behaviour and alertness. That often says more than the number alone.
Frequently asked questions
Below are the questions we hear most often about sodium later in life.
References
- Filippatos TD, Makri A, Elisaf MS, Liamis G. Hyponatremia in the elderly: challenges and solutions. Clin Interv Aging. 2017;12:1957-1965. PMID: 29180859.
- Thuisarts.nl. I have a low sodium in my blood (hyponatraemia). Accessed 2026. thuisarts.nl.
- Dutch Pharmacotherapeutic Compass (Farmacotherapeutisch Kompas). Diuretics and SSRIs. Accessed 2026. farmacotherapeutischkompas.nl.
Would you like to have your sodium and other values checked at a calm moment, without first booking an appointment with your GP? At Levenswijs Health you can. Every result is reviewed by a doctor registered in the Dutch BIG register. A blood test does not provide a diagnosis. For treatment decisions, always discuss your results with your GP.
Często zadawane pytania
What are the symptoms of a low sodium?
Often these are drowsiness, headache, confusion, muscle weakness and sometimes falls. A slightly lowered sodium often gives no complaints, a stronger drop does. The complaints are non-specific, so a blood test gives direction but does not provide a diagnosis.
Why am I more likely to get a low sodium with age?
The kidneys regulate the fluid and salt balance less tightly with age, and widely used medicines such as water pills and some antidepressants can lower sodium. Drinking a lot can also play a part. Discuss concerns with your GP.
Should I drink less water with a low sodium?
Not on your own initiative. Both too much and too little drinking can disturb the balance, and the right approach depends on the cause. Have it looked into and follow your GP's advice.
Do I need a referral to have sodium measured?
No. At Levenswijs you can have your sodium measured without a referral. The result is reviewed by a doctor registered in the Dutch BIG register. For treatment, your GP remains your point of contact.
Autor
