Written in alignment with NHS England hypertension guidance and NICE clinical guidelines. This page is for informational purposes only — always consult your GP for medical assessment.
What Are the Signs of High Blood Pressure?
High blood pressure — medically known as hypertension — is one of the UK's most serious and widespread health conditions, affecting approximately one in three adults. It is a primary driver of heart attacks, strokes, kidney failure, and vascular dementia. And yet, despite all this damage it silently causes, the most important thing to understand about the signs of high blood pressure is this: most people have none at all.
This is why hypertension has earned the grim nickname the "silent killer." A person can walk around for years with blood pressure consistently above 160/100 mmHg — damaging their heart, kidneys, arteries, and brain — without feeling any different from someone whose blood pressure is perfectly healthy. The only reliable way to detect hypertension is to measure blood pressure directly, which is why the NHS recommends regular monitoring for all adults.
⚠️ The most important fact about high blood pressure symptoms: In the vast majority of cases, there are no symptoms. Do not wait for warning signs. If you are aged 40 or over and have not had your blood pressure checked in the last 5 years, speak to your GP or use an NHS Health Check. Use our Blood Pressure Calculator NHS to understand your reading and see the full Blood Pressure Chart UK.
When Symptoms of Hypertension Do Occur
While most people with high blood pressure have no symptoms, there are circumstances where symptoms of hypertension can appear. These are most commonly associated with severely elevated blood pressure — typically above 180/120 mmHg — or with a hypertensive crisis, which requires immediate emergency treatment.
When blood pressure rises to dangerously high levels, symptoms may include some or all of the following. It is important to note that these symptoms can also have many other causes — they are not specific to hypertension — but if they occur alongside a very high blood pressure reading, they should be treated as a medical emergency.
Severe Headache
Particularly at the back of the head and on waking. Hypertension headaches tend to be pressure-type rather than throbbing, and may be present on waking before activity or stimulants. Routine elevated BP (140–160 mmHg) rarely causes headache.
Blurred or Double Vision
Very high blood pressure can damage the blood vessels in the retina (hypertensive retinopathy), causing visual disturbance. Sudden vision changes alongside a high BP reading require urgent medical assessment.
Shortness of Breath
Breathing difficulty can occur when very high BP causes acute heart strain. Breathlessness at rest, or that comes on suddenly, alongside a high BP reading is a potential emergency symptom.
Chest Pain or Tightness
Chest pain is not a typical sign of stable high blood pressure, but it can occur during a hypertensive crisis as the heart works against significantly elevated resistance. Any chest pain with a high BP reading requires 999.
Nosebleeds
The link between nosebleeds and high blood pressure is frequently overstated. Nosebleeds are rarely caused by hypertension at common ranges. However, very severe hypertension (above 180/120 mmHg) can occasionally cause nosebleeds, particularly with other symptoms.
Dizziness or Confusion
Dizziness alone is not a reliable sign of high blood pressure and is more often associated with low blood pressure. However, severe hypertension can occasionally cause confusion or altered consciousness, particularly in hypertensive encephalopathy.
Why High Blood Pressure Is Usually Silent
Understanding why hypertension causes no symptoms in most cases requires a brief look at the physiology. Blood pressure represents the force your blood exerts against artery walls. When this force is chronically elevated, it gradually damages arterial walls, the heart muscle, kidney tissue, and retinal vessels. This process is slow and painless. The arteries adapt over time, the heart muscle thickens compensatorily, and the kidneys filter less efficiently — all without producing any sensation that would alert the individual to a problem.
Symptoms tend to appear only when the damage reaches a threshold, or when blood pressure rises so acutely that the body's compensatory mechanisms cannot keep pace. By the time symptoms do appear, significant organ damage may already have occurred. This is why prevention and early detection — through regular blood pressure monitoring — are so vastly more effective than waiting for symptoms.
Blood Pressure Numbers Explained
A blood pressure reading consists of two numbers measured in millimetres of mercury (mmHg):
- Systolic pressure (top number): The pressure in your arteries when your heart beats and pumps blood. The more force your heart uses, the higher this number. Normal is below 120 mmHg; hypertension is diagnosed when consistently 140 mmHg or above.
- Diastolic pressure (bottom number): The pressure in your arteries between heartbeats, when the heart is resting and refilling. Normal is below 80 mmHg; hypertension threshold is 90 mmHg or above.
A reading of 140/90 mmHg or above on repeated measurements is the NHS threshold for diagnosing hypertension. A reading of 180/120 mmHg or above constitutes a hypertensive crisis requiring immediate emergency medical treatment.
| Reading | NHS Classification | Action Required |
|---|---|---|
| Below 120/80 mmHg | Optimal | Maintain healthy lifestyle |
| 120–129/80–84 | Normal | Healthy habits, annual check |
| 130–139/85–89 | High Normal | Lifestyle changes; 6-month recheck |
| 140–159/90–99 | High (Stage 1) | GP assessment; medication consideration |
| 160–179/100–109 | High (Stage 2) | Urgent GP appointment same day |
| 180+/120+ | Hypertensive Crisis | Call 999 immediately — emergency |
Risk Factors for High Blood Pressure
Understanding the high blood pressure risk factors is essential because, given the lack of symptoms, the only proactive approach is to know whether you are at elevated risk and monitor accordingly. The NHS and NICE identify the following key modifiable and non-modifiable risk factors:
Non-Modifiable Risk Factors
- Age: Blood pressure rises with age as arteries gradually stiffen. Over 65% of UK adults aged 65 and over have hypertension.
- Family history: Having a close relative with hypertension significantly increases your risk, suggesting a genetic component.
- Ethnicity: People of Black African or Caribbean heritage face significantly higher risk of hypertension, often developing it younger and at more severe levels. South Asian adults also have elevated cardiovascular risk at equivalent blood pressures.
- Sex: Under 65, men are more commonly affected. Over 65, the rates converge.
Modifiable Risk Factors
- Excess body weight: BMI above 25 significantly increases blood pressure. Losing 5–10% of body weight can reduce systolic pressure by 5–20 mmHg. Use our NHS Weight Loss Calculator to plan safe weight reduction, and our NHS Healthy BMI Range Calculator to set a healthy weight target.
- High salt intake: The NHS recommends no more than 6 g of salt per day. Most UK adults consume significantly more. Excess salt causes the kidneys to retain water, increasing blood volume and pressure.
- Physical inactivity: Regular aerobic exercise — at least 150 minutes of moderate intensity per week — reduces systolic blood pressure by 5–8 mmHg on average.
- Excessive alcohol: Consuming more than 14 units per week consistently raises blood pressure. Reducing alcohol to NHS recommended limits can lower systolic pressure by 2–4 mmHg.
- Smoking: Each cigarette temporarily raises blood pressure. Long-term smoking damages arterial walls, accelerating atherosclerosis and increasing cardiovascular risk.
- Poor sleep: Obstructive sleep apnoea (where breathing repeatedly stops during sleep) is strongly associated with hypertension.
- Chronic stress: Prolonged psychological stress activates the sympathetic nervous system, chronically elevating heart rate and blood pressure over time.
When to Seek Medical Help for High Blood Pressure
The challenge of hypertension is knowing when action is needed when there are no symptoms. Here is a clear NHS-aligned framework for when to seek help:
Call 999 Immediately If:
Blood pressure reading is 180/120 mmHg or above AND you have any of: severe headache, chest pain, shortness of breath, sudden vision changes, confusion, signs of stroke (facial drooping, arm weakness, speech difficulty). Do not drive yourself — call 999.
⚠️ See your GP urgently (same day) if: Blood pressure is 160/100 mmHg or above, even without symptoms. Or if you have any concerning symptoms alongside a reading above 140/90 mmHg, including chest discomfort, visual changes, or severe headache.
ℹ️ Book a routine GP appointment if: Home readings consistently above 135/85 mmHg on multiple occasions (morning and evening for 7 days); you have risk factors for hypertension and have not been checked in over 5 years; you are over 40 and due for an NHS Health Check.
How to Reduce High Blood Pressure: NHS-Aligned Lifestyle Changes
For most people in the high-normal or Stage 1 hypertension range, lifestyle changes alone can bring blood pressure back to a healthy level without medication. The NHS recommends a multi-factorial approach combining several lifestyle modifications simultaneously, as the combined effect is greater than any single change:
- Reduce salt to under 6 g/day — check food labels, avoid adding salt at the table, and cook from scratch where possible
- Increase potassium-rich foods — bananas, potatoes, pulses, and leafy greens help counteract sodium's blood pressure effect
- Follow the DASH dietary approach — high in fruit, vegetables, wholegrains, and low-fat dairy; low in saturated fat and processed food
- Exercise regularly — 150 minutes of moderate aerobic activity per week (brisk walking, cycling, swimming). Check your cardiovascular risk with our QRISK Calculator NHS
- Achieve and maintain a healthy weight — use our Ideal Weight Calculator UK and the safe rate of weight loss guide for an NHS-aligned plan
- Limit alcohol to 14 units per week — spread across at least 3 days; have alcohol-free days each week
- Stop smoking — the NHS Stop Smoking Service significantly improves success rates
- Manage stress — regular physical activity, adequate sleep (7–9 hours), and relaxation techniques reduce sympathetic nervous system activation
- Stay hydrated — adequate hydration supports blood viscosity and kidney function. Use our Water Intake Calculator NHS
💡 For complete health monitoring: Blood pressure is most meaningful when considered alongside other risk factors. Use our QRISK Calculator NHS for a 10-year cardiovascular risk estimate, our Visual BMI Calculator to assess weight-related risk, and our General Health Weight Ratios tool for waist-based risk measures. For children's health, see our Child Growth Chart UK and Child BMI Calculator NHS.
Frequently Asked Questions
The most important fact about signs of high blood pressure is that most people have none. Hypertension is called the "silent killer" precisely because it causes no symptoms in the vast majority of cases, even when dangerously elevated. When symptoms do occur — typically only at very high readings above 180/120 mmHg — they may include severe headache (particularly at the back of the head), blurred vision, chest pain, shortness of breath, nosebleeds, and dizziness. Use the checker above to assess your reading, or visit our Blood Pressure Calculator NHS for full category guidance.
High blood pressure can cause headaches, but this is much less common than widely believed. Headaches associated with hypertension typically occur only when blood pressure is severely elevated (above 180/120 mmHg). They tend to be felt at the back of the head and may be present on waking. Routine hypertension at 140–160/90–100 mmHg rarely causes headaches. Having a headache is not a reliable indicator of high blood pressure — most headaches have other causes. If you're concerned, measure your blood pressure and see our Blood Pressure Chart UK.
NHS guidelines define 180/120 mmHg or higher as a hypertensive crisis requiring immediate emergency medical attention — call 999. Blood pressure consistently above 160/100 mmHg requires urgent same-day GP assessment. Consistently above 140/90 mmHg is diagnosed as hypertension requiring GP discussion and potential treatment. Normal is below 120/80 mmHg; the optimal range is 90/60 to 120/80 mmHg. See the full NHS blood pressure category table above or use our Blood Pressure Calculator NHS.
Yes — the vast majority of people with high blood pressure have no symptoms whatsoever. Approximately 1 in 3 UK adults has hypertension, and many are completely unaware because they feel perfectly well. This is why regular blood pressure screening is essential: NHS guidance recommends checking every 5 years for adults (more frequently if readings are elevated), and the NHS Health Check programme offers free checks for adults aged 40–74 in England. Do not rely on symptoms to detect high blood pressure.
The most common type — essential (primary) hypertension — has no single identified cause but is strongly associated with: older age, excess body weight (use our NHS Healthy BMI Range Calculator to check), family history, high salt intake, physical inactivity, excessive alcohol, smoking, chronic stress, and poor sleep. Secondary hypertension (less common) results from underlying conditions such as kidney disease, thyroid disorders, or obstructive sleep apnoea. Black African and Caribbean heritage is associated with higher hypertension risk.
Call 999 immediately if your reading is 180/120 mmHg or above AND you have symptoms. See your GP urgently (same day) if readings are consistently 160/100 mmHg or above. Book a routine appointment if home readings are consistently above 135/85 mmHg on multiple occasions over a week, or if you have known risk factors and haven't been checked in more than 5 years. Check your reading and get full guidance from our Blood Pressure Calculator NHS.
The NHS defines normal blood pressure as below 120/80 mmHg. The ideal range is between 90/60 mmHg and 120/80 mmHg. Readings of 120–139/80–89 are considered elevated or high-normal, warranting lifestyle attention. High blood pressure (hypertension) is 140/90 mmHg or above. See the full NHS blood pressure category table on this page, or use our Blood Pressure Chart UK for a complete reference.
Yes — significantly. Excess body weight is one of the strongest modifiable risk factors for hypertension. Losing 5–10% of body weight can reduce systolic blood pressure by 5–20 mmHg in overweight individuals. Even small weight reductions produce meaningful improvements. The NHS recommends combining weight loss with exercise, salt reduction, and alcohol reduction for maximum blood pressure benefit. Use our NHS Weight Loss Calculator for a personalised plan and the safe rate of weight loss guide for the science behind gradual fat loss.