68 Harley Street London, W1G 7HE · Main Office
Also at Cromwell & Syon Bishops Wood · Multiple Locations
0203 9838 001 Call for Appointments
jessica@oneheartclinic.com Rapid Response to Enquiries
High blood pressure — your questions answered
Around one in three UK adults has high blood pressure, and roughly half of them do not know it. Hypertension causes no symptoms until damage is already done — which is why it is sometimes called the silent killer. The encouraging news is that well-controlled blood pressure dramatically reduces the risk of stroke, heart attack, kidney disease and dementia. I answer the most common questions here.
High blood pressure management at One Heart Clinic
High blood pressure rarely causes symptoms until it causes a complication — which is why Dr Nijjer calls it the 'silent risk.' Proper assessment goes beyond a single reading to understand your overall cardiovascular risk.
- Comprehensive blood pressure assessment including home monitoring
- 24-hour ambulatory BP monitoring to detect white-coat and masked hypertension
- Echocardiogram to detect silent cardiac effects
- Full cardiovascular risk assessment (QRISK, cholesterol, kidney function)
Blood pressure assessment at One Heart Clinic, Harley Street
When high blood pressure is an emergency — call 999
Very high blood pressure (typically above 180/120) combined with any of the following is a hypertensive emergency requiring immediate hospital assessment:
- Chest pain or severe headache
- Visual disturbance or confusion
- Breathlessness, weakness or speech difficulty
- Blood in the urine
Questions on this page
- What is a normal blood pressure reading?
- At what blood pressure should I see a cardiologist?
- Can high blood pressure be cured without medication?
- Why is my blood pressure higher at the doctor's?
- What are the symptoms of high blood pressure?
- Is blood pressure of 140/90 dangerous?
- How quickly do blood pressure tablets start working?
- Why is my blood pressure suddenly high?
- Can young people get high blood pressure?
- Should I check my blood pressure at home, and how?
- What foods raise blood pressure the most?
- Does treating high blood pressure prevent strokes?
What is a normal blood pressure reading?
A normal blood pressure for most adults is below 120/80 mmHg. Under current UK NICE definitions, readings of 120–139/80–89 are classified as high-normal, 140/90 or above (or 135/85 on home monitoring) is stage 1 hypertension, and 160/100 or above is stage 2 hypertension.
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Normal | Below 120 | Below 80 |
| High-normal | 120–139 | 80–89 |
| Stage 1 hypertension | 140–159 | 90–99 |
| Stage 2 hypertension | 160 or above | 100 or above |
| Hypertensive emergency | 180 or above | 120 or above (with symptoms) |
A single high reading is not a diagnosis — blood pressure fluctuates with time of day, stress, caffeine, posture and even a full bladder. Confirmation usually requires repeated office readings, a week of home readings, or a 24-hour ambulatory monitor.
At what blood pressure should I see a cardiologist?
You should see a cardiologist if your blood pressure is consistently 140/90 or above despite lifestyle changes, if you are on three or more blood pressure medications and still not controlled (resistant hypertension), if you are young (under 40) with hypertension, or if there is suspicion of a secondary cause such as kidney or adrenal disease.
Specialist review also adds value if your blood pressure is normal in clinic but elevated at home (masked hypertension), or if you have already had a cardiovascular event such as a stroke or heart attack. Most uncomplicated hypertension is managed well by GPs — specialist input adds most at the harder edges.
"Blood pressure is a perfect example of silent risk. Most of my patients with hypertension had no symptoms whatsoever — they only know about it because someone measured it. The encouraging thing is that treating it effectively is very achievable, and the protection against stroke and heart attack is substantial. Every millimetre reduction genuinely matters."
— Dr Sukhjinder Nijjer, Consultant Cardiologist, Harley Street
Can high blood pressure be cured without medication?
For many people with mild hypertension, lifestyle changes alone can normalise blood pressure. Weight loss (around 1 mmHg drop per kg lost), a Mediterranean or DASH-style diet, reducing salt to below 6 g a day, limiting alcohol, regular aerobic exercise (150 minutes a week) and stopping smoking can together reduce systolic blood pressure by 10–20 mmHg.
Whether that is enough to avoid medication depends on your baseline reading and your overall cardiovascular risk. Most people with stage 2 hypertension will need both lifestyle changes and medication, while many with stage 1 can hold off medication if they commit to sustained lifestyle change. See also heart health and lifestyle FAQs.
Why is my blood pressure higher at the doctor's? (white coat hypertension)
White coat hypertension is the phenomenon of blood pressure rising in clinical settings due to anxiety, even in people whose readings at home are normal. It is common — around one in five patients with raised clinic readings has it.
The fix is to confirm with home monitoring or a 24-hour ambulatory monitor before committing to lifelong medication. NICE actually recommends this routinely whenever a clinic reading is 140/90 or above. White coat hypertension is not entirely benign — affected patients have a modestly increased risk of developing true hypertension over time, so periodic re-checking is wise.
Dr Nijjer's clinical perspective Consultant Cardiologist · One Heart Clinic, 68 Harley Street
High blood pressure is one of the most treatable cardiovascular risk factors, yet remains underdiagnosed and undertreated. In my clinic I see patients who have had mildly elevated readings for years without proper investigation — and in many cases a single echocardiogram reveals that the heart has already started to enlarge silently in response.
My approach goes beyond the blood pressure reading itself. I assess overall cardiovascular risk, check for end-organ effects with an echocardiogram, and use 24-hour ambulatory monitoring to confirm the diagnosis and guide treatment. For patients with difficult-to-control hypertension, I investigate secondary causes including renal artery stenosis. The goal is not just a lower number — it is a genuinely reduced risk of stroke and heart attack.
UK blood pressure classification
Based on NICE guidelines. Readings are in mmHg (systolic / diastolic).
Category
Systolic
Diastolic
Optimal
< 120
< 80
Normal
120–129
< 80
High-normal
130–139
85–89
Stage 1 hypertension
140–159
90–99
Stage 2 hypertension
≥ 160
≥ 100
What are the symptoms of high blood pressure?
In most people, high blood pressure causes no symptoms at all, which is why it has to be screened for rather than waited for. By the time symptoms appear — typically headaches, visual changes, nosebleeds, breathlessness or chest pain — the blood pressure is usually severely elevated and complications may already be developing.
This is the reason for the NHS Health Check from age 40, and for the recommendation that everyone over 18 should have their blood pressure checked at least every five years. Do not wait for symptoms to investigate your blood pressure.
"I find it genuinely rewarding to treat hypertension. It's one of those conditions where the evidence is crystal clear — lower the blood pressure and you prevent strokes, heart attacks and kidney failure. When I see a patient go from a systolic of 170 to 120 on treatment, I know we've substantially changed their long-term outlook."
— Dr Sukhjinder Nijjer
Is blood pressure of 140/90 dangerous?
A blood pressure of 140/90 is the threshold for stage 1 hypertension and is associated with a meaningfully increased long-term risk of stroke, heart attack, kidney disease and dementia. The danger from 140/90 is cumulative over years and decades, not from any single reading.
How it is managed depends on your overall cardiovascular risk. NICE recommends treatment for stage 1 hypertension when there is target organ damage, established cardiovascular disease, kidney disease, diabetes, or a 10-year QRISK score above 10%. Below that threshold, lifestyle changes and re-checking are the first steps.
How quickly do blood pressure tablets start working?
Most blood pressure medications start lowering blood pressure within hours of the first dose, but the full effect builds over 2–6 weeks. This is why doctors usually wait at least two to four weeks before adjusting a dose or adding another agent.
Side effects, when they occur, typically appear in the first 1–2 weeks and often settle. A common early experience is feeling slightly tired or light-headed — this usually reflects your body adjusting to a lower blood pressure and resolves within a week or two. Do not stop a medication abruptly without speaking to your doctor.
Why is my blood pressure suddenly high?
A sudden rise in blood pressure can be triggered by acute stress, severe pain, alcohol withdrawal, missed medication doses, decongestants and certain over-the-counter painkillers — especially NSAIDs like ibuprofen — and stimulant medications including some cold remedies and ADHD treatments.
A persistent unexplained rise — particularly in someone whose blood pressure was previously well controlled — should prompt review for secondary causes. These include kidney artery narrowing, thyroid disorders, primary aldosteronism (an adrenal hormone problem), sleep apnoea and, occasionally, a rare adrenal tumour called a phaeochromocytoma.
"One thing I always ask younger patients with high blood pressure is about their salt intake, their sleep quality and whether they've ever been told they snore. Sleep apnoea is a surprisingly common and very treatable cause of resistant hypertension — and finding it changes the whole management approach."
— Dr Sukhjinder Nijjer
Can young people get high blood pressure?
Yes — and the proportion of young adults with hypertension is rising, driven by obesity, salt intake, poor sleep and alcohol. Around one in twelve adults under 40 in the UK has high blood pressure, although awareness and treatment rates in this age group are particularly low.
Hypertension in someone under 40 should always trigger a search for a secondary cause, because the chance of a treatable underlying condition is higher than in older patients. Common findings include kidney problems, primary aldosteronism, sleep apnoea and — in young women — oral contraceptive-related hypertension.
Should I check my blood pressure at home, and how?
Yes — home blood pressure monitoring is one of the most useful things a hypertensive patient can do, and modern validated machines are accurate and inexpensive. Use an upper-arm cuff (not a wrist device) from the British Hypertension Society approved list.
To take an accurate reading: sit quietly for five minutes, feet flat on the floor, back supported, arm supported at heart height, cuff on bare skin. Take two readings one minute apart, twice a day (morning and evening) for seven days, and average the readings after discarding day one. Home averages of 135/85 or above suggest hypertension.
What foods raise blood pressure the most?
The single biggest dietary driver of high blood pressure is salt. Most of the salt we eat is hidden in processed foods — bread, ready meals, sauces, processed meats, cheese and takeaways — rather than from the salt cellar. UK adults eat around 8 g a day on average; the target is under 6 g.
Other significant culprits are excess alcohol (more than 14 units a week), liquorice in large amounts, caffeine in sensitive individuals, and ultra-processed foods generally. The DASH diet — rich in fruit, vegetables, wholegrains, nuts, pulses and low-fat dairy — has been shown to lower blood pressure as effectively as a single medication.
Does treating high blood pressure prevent strokes?
Yes — emphatically. Treating high blood pressure is one of the most effective interventions in medicine. A 10 mmHg reduction in systolic blood pressure reduces the risk of stroke by around 27% and the risk of heart attack by around 17%.
The benefits begin within months of starting treatment and accumulate over years. For most people, the protection from a daily tablet vastly outweighs any side effects — but the choice and combination of medication should be tailored to you, your other conditions and your tolerability.
Related conditions and investigations
See Dr Nijjer for a hypertension assessment
Dr Nijjer offers comprehensive hypertension assessments with 24-hour ambulatory blood pressure monitoring, screening for secondary causes, and personalised treatment plans tailored to your overall cardiovascular risk.
Book a ConsultationTrusted external resources
This page provides general information for educational purposes and is not a substitute for personalised medical advice, diagnosis or treatment. In a medical emergency, call 999. Last reviewed ; next review due .