A silent stroke causes no obvious symptoms but leaves real damage behind. Here is what it is, why it matters in midlife and the dull habits that help prevent one.
Reviewed, edited and approved by Editor-in-chief Daniel Sköld · Updated 31 October 2026
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Most of us know the classic stroke picture: the drooping face, the arm that won’t lift, the words coming out jumbled. It is dramatic, frightening and, thankfully, hard to miss.
There is a quieter version that nobody notices at all. No ambulance and no drama, just a small patch of brain tissue that has died because its blood supply was cut off. Plenty of men only find out years later, when a scan done for something else shows the scars. If you are in your late forties or fifties, it is worth knowing about.
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What is a silent stroke?
A stroke happens when the blood supply to part of the brain is cut off, usually because a blood vessel is blocked and sometimes because one bursts. Without oxygen, brain cells die. The NHS calls it a medical emergency, and it is right to.
A silent stroke works the same way but on a smaller scale. Typically a tiny artery deep in the brain gets blocked. The damaged area is small, or it sits somewhere that doesn’t control anything you would obviously miss, such as movement, speech or sight. So you notice nothing. You carry on with your day and the damage stays put.
Doctors usually spot these old injuries by chance on an MRI or CT scan done for headaches, dizziness or a knock on the head. On the scan they show up as small dark spots, often called lacunar infarcts, sometimes alongside wider changes in the brain’s white matter. Together these point to what specialists call small vessel disease: the brain’s smallest arteries slowly stiffening and narrowing.
If I didn’t notice it, does it matter?
Sadly, yes. A silent stroke doesn’t announce itself, but it isn’t harmless.
First, it is a warning. Having had one is linked to a higher chance of a full-blown, symptomatic stroke later. The plumbing that failed quietly once can fail loudly next time.
Second, the damage adds up. One tiny injury may change nothing you could measure. Several over the years, plus steady wear on the small vessels, can start to affect thinking. Small vessel disease is one of the main causes of vascular dementia, the second most common type of dementia in the UK after Alzheimer’s disease. The NHS describes vascular dementia as caused by reduced blood flow to the brain, and the early signs can be subtle: slower thinking, trouble planning or concentrating, getting more muddled than you used to, mood changes and walking that becomes a bit unsteady.
None of that means a forgetful week is a stroke. Losing your car keys is a long and honourable midlife tradition. But a gradual change that people close to you can see is worth raising with your GP.
A silent stroke isn’t silent because it is harmless. It is silent because nobody was listening.
Who is most at risk of a silent stroke?
The risk factors are the same as for any stroke, and most of them are familiar from every heart health leaflet you have binned.
High blood pressure leads the list. It is the biggest single risk factor for stroke, and it usually has no symptoms, so millions of people have it without knowing. Years of raised pressure batter the delicate small arteries in the brain, which is exactly where silent strokes tend to happen.
Close behind are smoking, type 2 diabetes, high cholesterol, being overweight, inactivity and drinking heavily. Atrial fibrillation, an irregular heart rhythm that lets clots form in the heart, raises stroke risk a lot and can also go unnoticed. Age matters too, and so does family history, though you can’t do much about either.
The good news is in the first list. Most of those factors can be measured, and most can be changed.
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How do I find out if I’m at risk?
A scan isn’t the answer. Nobody is offered a brain MRI on the NHS just to look for silent strokes, and private scans can turn up minor findings that cause a lot of worry without giving you anything useful to do. The practical approach is to check the things that cause them.
In England, adults aged 40 to 74 with no existing heart disease, stroke, diabetes or kidney disease are invited for a free NHS Health Check every five years. It covers blood pressure, cholesterol, weight and lifestyle, and gives you an estimate of your risk of heart disease and stroke. If you haven’t been invited, ask your GP practice. Scotland, Wales and Northern Ireland don’t run the same programme, so contact your GP practice or a community pharmacy there to ask about a blood pressure and cholesterol check.
Many pharmacies across the UK will check your blood pressure, and a home monitor from a chemist costs less than a decent pair of shoes. If your readings keep coming back high, take them to your GP. They are also worth a GP visit if you get a fluttering or irregular pulse, palpitations or unexplained breathlessness, all of which can come with atrial fibrillation.
What actually lowers the risk?
This is the dull part, and dull works. Keep your blood pressure under control, whether through lifestyle changes alone or with treatment your GP recommends. If you are prescribed medicine for blood pressure, cholesterol or an irregular heartbeat, talk to your GP or pharmacist before changing how you take it.
Stop smoking. Free NHS stop smoking services across the UK give you a much better chance of quitting than willpower alone. Keep to the UK Chief Medical Officers’ low-risk guideline of no more than 14 units of alcohol a week, spread over three or more days. Aim for at least 150 minutes of moderate activity a week, such as brisk walking or cycling, plus some strength work. Eat less salt, more fibre and more vegetables, and if your waistline has crept up, losing even a modest amount of weight helps your blood pressure.
No supplement has good evidence for preventing silent strokes, whatever the adverts claim. Fish oil capsules and brain-boosting pills aren’t a substitute for getting your blood pressure down.
Finally, know the signs of a stroke that isn’t silent. The NHS uses FAST: Face drooping, Arms that can’t be lifted, Speech that is slurred, Time to call 999. Call even if the symptoms pass quickly. A mini-stroke, or transient ischaemic attack, can clear up within minutes and is a strong warning that a bigger stroke may follow, so it needs urgent assessment.
In short
A silent stroke is a small blockage in the brain that causes no obvious symptoms, but it raises your chance of a major stroke and, over time, of vascular dementia. You can’t feel one, but you can measure the things that cause them, with high blood pressure top of the list. Get your blood pressure and cholesterol checked through the free NHS Health Check in England or your GP practice or pharmacy elsewhere in the UK, act on the results and call 999 for any FAST symptoms.
Adrian Irving writes about health for men 45 and over who would rather do something than worry. Training, weight loss, sleep, cholesterol and blood tests, heart health, testosterone, the prostate, mental health and your sex life – what the evidence says, what's worth trying, and when it's time to see your GP.
One of Midcent's writers. Spotted something? Write to adrian@midcent.uk.
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