High Blood Pressure (Hypertension): Numbers, Risks, Treatment and Prevention
High blood pressure, also called hypertension, is one of the world's most important preventable causes of cardiovascular disease and premature death.
It can damage the heart, brain, kidneys, blood vessels and other organs over time.
Yet there is something unusual about hypertension:
Most people who have it do not feel ill.
You can have high blood pressure for years without obvious warning signs.
The only reliable way to know your blood pressure is to measure it properly.
Fortunately, hypertension can often be successfully controlled through lifestyle changes, medicines or a combination of both.
What Is Blood Pressure?
Blood pressure is the force created as circulating blood pushes against the walls of your arteries.
A blood-pressure reading contains two numbers.
For example:
120/80 mmHg
The first number is called systolic blood pressure.
The second is called diastolic blood pressure.
What Does Systolic Blood Pressure Mean?
Systolic pressure is the pressure in your arteries when your heart contracts and pumps blood around your body.
It is the top number in a blood-pressure reading.
For example, in a reading of 120/80 mmHg, 120 is the systolic pressure.
What Does Diastolic Blood Pressure Mean?
Diastolic pressure is the pressure in your arteries while the heart relaxes between beats.
It is the bottom number.
In a reading of 120/80 mmHg, 80 is the diastolic pressure.
Both numbers matter.
What Does mmHg Mean?
Blood pressure is measured in millimetres of mercury, abbreviated as mmHg.
The unit comes from the traditional mercury instruments historically used to measure blood pressure.
Modern digital monitors generally no longer contain mercury, but the measurement unit remains the same.
What Blood Pressure Is Considered High?
This is where readers need to understand an important point:
Hypertension thresholds are not identical in every international guideline.
The World Health Organization defines hypertension in adults as:
Systolic blood pressure of 140 mmHg or higher and/or diastolic blood pressure of 90 mmHg or higher, when elevated readings are confirmed on two different days.
Some professional guidelines use lower thresholds.
For example, current American cardiovascular guidelines classify blood pressure beginning at 130/80 mmHg as hypertension.
Therefore, a reading should always be interpreted using the clinical guidelines applicable where you live and your individual cardiovascular risk.
Does One High Reading Mean You Have Hypertension?
Not necessarily.
Blood pressure naturally changes throughout the day.
It can temporarily increase because of factors such as:
- physical activity,
- stress or anxiety,
- caffeine,
- tobacco,
- alcohol,
- pain,
- some medicines,
- and incorrect measurement technique.
A diagnosis is normally based on repeated measurements rather than one isolated reading, except when extremely high blood pressure or a medical emergency requires immediate action.
Some people have higher readings in a clinic but normal readings outside the clinic. This is sometimes called white-coat hypertension.
Others can have normal clinic readings but elevated blood pressure at home, known as masked hypertension.
Home or ambulatory monitoring can therefore sometimes help confirm the diagnosis.
Hypertension Usually Has No Symptoms
This is one of the most important facts about high blood pressure.
Most people with hypertension experience no symptoms.
Someone can feel perfectly healthy while high blood pressure is gradually damaging blood vessels and organs.
This is why hypertension is sometimes described as a “silent” condition.
Do not rely on headaches, dizziness or nosebleeds to tell you whether your blood pressure is high.
Measure it.
Can Very High Blood Pressure Cause Symptoms?
Yes.
Very high blood pressure can sometimes occur with symptoms, particularly when it is causing acute organ damage.
Possible warning symptoms can include:
- severe headache,
- chest pain,
- difficulty breathing,
- weakness or numbness,
- changes in vision,
- difficulty speaking,
- confusion,
- and other sudden neurological symptoms.
These should not be treated as routine symptoms of ordinary hypertension.
They may indicate a serious medical problem requiring urgent assessment.
Why Is High Blood Pressure Dangerous?
Persistent high blood pressure places extra stress on arteries and organs.
Over time, it can increase the risk of:
- heart disease,
- heart attack,
- stroke,
- heart failure,
- chronic kidney disease,
- vision problems,
- and other vascular complications.
Controlling blood pressure substantially reduces cardiovascular risk.
High Blood Pressure and Stroke
Hypertension is a major risk factor for stroke.
Persistently elevated pressure can damage blood vessels supplying the brain.
A stroke can occur when blood flow to part of the brain becomes blocked or when a blood vessel ruptures and bleeds.
Stroke can cause permanent disability or death.
High Blood Pressure and the Heart
The heart has to work against the pressure in the arterial system.
Over time, uncontrolled hypertension can contribute to:
- coronary artery disease,
- heart attack,
- enlargement or thickening of the heart muscle,
- and heart failure.
Managing blood pressure is therefore an important part of protecting cardiovascular health.
High Blood Pressure and the Kidneys
The kidneys contain networks of small blood vessels that filter waste and excess fluid from the blood.
High blood pressure can damage these vessels.
At the same time, kidney disease can itself cause or worsen hypertension.
This creates an important relationship:
High blood pressure can damage the kidneys, and kidney disease can raise blood pressure.
People with hypertension may therefore have blood and urine tests to assess kidney health.
High Blood Pressure and the Eyes
Very high or long-standing uncontrolled hypertension can damage blood vessels in the retina at the back of the eye.
This is known as hypertensive retinopathy.
Severe hypertension can sometimes cause visual symptoms.
However, eye examination is not the main test used to diagnose hypertension.
Blood-pressure measurement is.
What Causes High Blood Pressure?
For many adults, there is no single identifiable disease responsible for their hypertension.
This is generally called primary or essential hypertension.
It tends to develop gradually through a combination of genetics, ageing, lifestyle, environment and other biological factors.
Another form is called secondary hypertension.
What Is Secondary Hypertension?
Secondary hypertension occurs when high blood pressure is caused by another medical condition or sometimes by a medicine or substance.
Possible causes can include:
- kidney disease,
- certain hormonal disorders,
- obstructive sleep apnoea,
- narrowing of certain arteries,
- some medicines,
- and certain recreational or stimulant drugs.
Treating the underlying cause may improve blood pressure in some people.
What Happened to “Malignant Hypertension”?
The old version of this KandyWandy article listed:
- primary hypertension,
- secondary hypertension,
- malignant hypertension.
That classification needs updating.
The term malignant hypertension has historically been used for severe hypertension associated with acute organ damage, particularly characteristic eye changes.
Modern clinical practice more commonly discusses hypertensive emergency when severely elevated blood pressure is accompanied by acute damage to organs such as the brain, heart, kidneys or eyes.
It is not simply a type of hypertension that “develops from an early age.”
What Increases Your Risk of Hypertension?
Risk factors include both things you can change and things you cannot.
They can include:
- increasing age,
- family history,
- overweight or obesity,
- high dietary sodium intake,
- diets low in fruit and vegetables,
- physical inactivity,
- tobacco use,
- excessive alcohol consumption,
- diabetes,
- kidney disease,
- and other metabolic or medical conditions.
Risk does not mean certainty.
Having one or several risk factors does not guarantee that hypertension will develop.
Is Hypertension Mainly a Male Problem?
No.
The old article stated that hypertension is “common with males.”
That is too simplistic.
High blood pressure affects both men and women.
Risk patterns can differ by age, hormonal status, pregnancy and other factors, but women should not assume they are protected from hypertension.
Everyone should have their blood pressure checked appropriately.
Does Age Cause High Blood Pressure?
The risk of hypertension generally increases with age.
However, high blood pressure should not simply be dismissed as “normal ageing.”
Older adults still benefit from appropriate blood-pressure management.
Treatment decisions may take into account overall health, frailty, other medical conditions and the risk of treatment side effects.
Does Salt Affect Blood Pressure?
Yes.
High sodium consumption is associated with increased blood pressure.
Much dietary sodium comes not only from salt added at the table but also from processed and packaged foods.
Foods that can contain substantial sodium include:
- processed meats,
- instant noodles,
- savoury snacks,
- sauces and condiments,
- some breads,
- ready meals,
- soups,
- and some canned foods.
But not every canned food is automatically unhealthy.
Check the nutrition label where available and compare sodium or salt levels.
Canned vegetables, beans or fish with little added salt can still form part of a nutritious diet.
Should You Add Extra Salt After Cooking?
The old article accidentally listed “adding extra salt to food after cooking” under hypertension prevention.
That advice is incorrect.
Reducing excessive salt intake can help lower blood pressure.
Taste food before adding salt and consider herbs, spices, garlic, ginger, lemon, pepper and other flavourings where appropriate.
Can Stress Cause Hypertension?
Stress can temporarily raise blood pressure.
Long-term stress may also influence behaviours associated with cardiovascular risk, including sleep, eating, alcohol consumption, smoking and physical activity.
However, “avoid all stress” is unrealistic.
A more practical approach is to develop healthy ways to manage stress through strategies such as:
- physical activity,
- adequate sleep,
- relaxation,
- social support,
- planning,
- and professional mental-health support when needed.
Does Smoking Cause High Blood Pressure?
Tobacco can temporarily raise blood pressure and heart rate and causes substantial damage to blood vessels.
Smoking is also a major cardiovascular risk factor independently of hypertension.
Stopping tobacco use is therefore one of the most important actions a person can take to protect cardiovascular health.
Alcohol and Blood Pressure
Excessive alcohol consumption can increase blood pressure.
Reducing alcohol intake can help some people improve blood-pressure control while also reducing other health risks.
People who do not drink alcohol do not need to start drinking for cardiovascular health.
Weight and Blood Pressure
Excess body weight can increase the likelihood of developing hypertension.
For people who are overweight or obese, gradual and sustainable weight loss may help reduce blood pressure.
However, blood pressure is influenced by many factors.
Thin people can develop hypertension too.
Physical Activity
Regular physical activity can help lower blood pressure and reduce cardiovascular risk.
WHO generally recommends that adults accumulate 150–300 minutes of moderate-intensity aerobic physical activity per week, or an equivalent amount of vigorous activity, together with muscle-strengthening activities.
People who have medical conditions or have been inactive for a long period may benefit from discussing an appropriate activity plan with a healthcare professional.
Healthy Eating for Blood Pressure
A heart-healthy eating pattern generally emphasizes:
- vegetables,
- fruits,
- whole grains,
- legumes,
- nuts and seeds where appropriate,
- healthier protein sources,
- and foods lower in excessive sodium, saturated fat and added sugars.
There is no single food that cures hypertension.
The overall dietary pattern matters more than a supposed “blood-pressure superfood.”
Potassium and Blood Pressure
Potassium-rich foods can form part of a healthy diet and may help counter some of sodium's effects on blood pressure.
Sources include various fruits, vegetables, beans and other foods.
However, people with kidney disease or those taking certain medicines may need to limit potassium.
Do not start potassium supplements or potassium-based salt substitutes without appropriate medical advice if you have kidney problems or take medicines that affect potassium levels.
How Is Hypertension Diagnosed?
The main diagnostic tool is simple:
accurate blood-pressure measurement.
Depending on the situation, diagnosis may involve:
- repeated clinic readings,
- home blood-pressure monitoring,
- or 24-hour ambulatory blood-pressure monitoring.
Blood tests, urine tests, ECGs and other investigations may be used to evaluate cardiovascular risk, organ health or possible causes of secondary hypertension.
But a chest X-ray, urine test or eye examination does not by itself diagnose hypertension.
How to Measure Blood Pressure Correctly
Accurate technique matters.
Before taking a home measurement:
- avoid smoking, caffeine and exercise for about 30 minutes beforehand where possible,
- empty your bladder,
- sit quietly for several minutes,
- keep your back supported,
- keep both feet flat on the floor,
- do not cross your legs,
- support your arm approximately at heart level,
- place the cuff on bare skin,
- use the correct cuff size,
- and remain quiet while the measurement is being taken.
A validated automatic upper-arm monitor is generally preferable for home monitoring.
Follow the instructions supplied with your device and recommendations from your healthcare team.
Take More Than One Reading
One measurement provides only a snapshot.
When monitoring at home, healthcare professionals commonly advise taking repeated readings according to a structured schedule.
If your first reading is unexpectedly high, remain calm and repeat the measurement after resting.
Record your results.
Your healthcare professional can tell you how frequently to measure and what numbers require action based on your individual circumstances.
Don't Change Medication Based on One Home Reading
Home monitoring is extremely useful, but it does not replace professional care.
Do not stop, double or change prescribed blood-pressure medicine simply because of one reading unless your healthcare professional has specifically given you instructions to do so.
Stopping some blood-pressure medicines suddenly can be harmful.
How Is High Blood Pressure Treated?
Treatment usually involves a combination of lifestyle measures and, when necessary, medication.
The appropriate plan depends on:
- blood-pressure level,
- cardiovascular risk,
- age,
- kidney function,
- diabetes,
- previous heart disease or stroke,
- pregnancy,
- other medical conditions,
- and tolerance of medicines.
There is no single medicine that is best for everyone.
Medicines for High Blood Pressure
Several groups of medicines can lower blood pressure.
Common classes include:
- thiazide or thiazide-like diuretics,
- ACE inhibitors,
- angiotensin receptor blockers (ARBs),
- and calcium-channel blockers.
Other medicines are used in particular circumstances.
Some people require more than one medicine to achieve good control.
WHO recommends several of these medicine classes as appropriate first-line options for adults requiring pharmacological treatment.
Should You Stop Medicine When Your Blood Pressure Becomes Normal?
Usually, no—not without medical advice.
If someone taking blood-pressure medication has normal readings, that may mean the medicine is working.
Stopping treatment can allow blood pressure to rise again.
Always discuss medication changes with the healthcare professional managing your treatment.
What Blood Pressure Should Treatment Aim For?
Targets depend on individual health and the guideline being followed.
WHO currently states that for most people with hypertension the goal is generally below 140/90 mmHg.
A lower target, generally below 130/80 mmHg, may be recommended for people with:
- cardiovascular disease,
- diabetes,
- chronic kidney disease,
- or high cardiovascular risk.
Targets can differ according to individual circumstances and national clinical guidelines.
Your healthcare professional should tell you the target appropriate for you.
What Is Severe Hypertension?
A blood pressure reading above 180/120 mmHg is severely elevated and requires attention.
If you obtain a reading in this range:
- remain seated and calm,
- wait at least one minute,
- measure your blood pressure again correctly.
If it remains above 180/120 mmHg, seek prompt medical advice.
When Is High Blood Pressure an Emergency?
Blood pressure above 180/120 mmHg together with symptoms suggesting acute organ damage can represent a hypertensive emergency.
Warning symptoms may include:
- chest pain,
- severe shortness of breath,
- weakness or numbness,
- difficulty speaking,
- sudden vision changes,
- severe neurological symptoms,
- confusion,
- or loss of consciousness.
Seek emergency medical care immediately or contact your local emergency medical service.
Do not wait at home hoping the blood pressure will fall by itself.
Hypertension During Pregnancy
High blood pressure during pregnancy requires special consideration.
Pregnancy-related hypertension and pre-eclampsia can endanger both the pregnant person and baby.
Symptoms that can occur with severe pre-eclampsia include:
- severe headache,
- visual disturbance,
- pain beneath the ribs or upper abdomen,
- nausea or vomiting,
- sudden swelling,
- and feeling seriously unwell.
Anyone who is pregnant and has high blood pressure or concerning symptoms should seek appropriate maternity or medical assessment.
Blood-pressure targets and medication choices during pregnancy differ from those used for non-pregnant adults.
Can Hypertension Be Prevented?
Not every case can be prevented because genetics, age and medical conditions can influence risk.
However, several measures can lower the likelihood of developing hypertension and help control existing high blood pressure.
These include:
- reducing excessive sodium intake,
- eating plenty of nutritious plant foods,
- being physically active,
- maintaining an appropriate body weight,
- avoiding tobacco,
- limiting alcohol,
- managing diabetes and other health conditions,
- getting adequate sleep,
- and checking blood pressure periodically.
If You Already Have Hypertension
Lifestyle changes remain valuable even when medication is required.
Good management often involves:
Know your numbers.
Take your medicine as prescribed.
Attend follow-up appointments.
Monitor at home if recommended.
Maintain healthy lifestyle habits.
Know when an unusually high reading needs medical attention.
Hypertension is often a long-term condition, but effective control can greatly reduce its risks.
The Bottom Line
High blood pressure is a common and serious condition that increases the risk of heart attack, stroke, heart failure, kidney disease and other health problems.
Most importantly:
Hypertension usually causes no symptoms.
Do not wait for a headache, dizziness or nosebleed before checking your blood pressure.
Accurate measurement is the only way to know your numbers.
Blood-pressure thresholds and treatment targets can vary somewhat between international guidelines, but persistently elevated blood pressure deserves appropriate medical assessment.
Lifestyle changes—including reducing excessive salt, exercising, maintaining metabolic health, avoiding tobacco and limiting alcohol—can help prevent and manage hypertension.
Many people also require medication.
If medicine has been prescribed, take it as directed and do not stop treatment simply because your readings improve.
Controlling blood pressure is one of the most effective ways to protect your heart, brain, kidneys and long-term health.
Medical Disclaimer
This article provides general health information for an international audience and is not a substitute for individual medical diagnosis or treatment. Blood-pressure thresholds, treatment targets and medication recommendations can vary according to medical history, pregnancy, cardiovascular risk and national guidelines. Consult an appropriately qualified healthcare professional for advice about your individual blood pressure. Seek emergency medical care for severely elevated blood pressure accompanied by serious symptoms such as chest pain, breathing difficulty, neurological weakness, difficulty speaking or sudden vision changes.
Sources and Further Reading
World Health Organization — Hypertension
https://www.who.int/news-room/fact-sheets/detail/hypertension
World Health Organization — Guideline for the Pharmacological Treatment of Hypertension in Adults
https://www.who.int/publications/i/item/9789240033986
Centers for Disease Control and Prevention — Measuring Your Blood Pressure
https://www.cdc.gov/high-blood-pressure/measure/index.html
Centers for Disease Control and Prevention — High Blood Pressure Risk Factors
https://www.cdc.gov/high-blood-pressure/risk-factors/
American Heart Association — Home Blood Pressure Monitoring
https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings/monitoring-your-blood-pressure-at-home
