High blood pressure (hypertension): symptoms, measuring and treatment

What high blood pressure is

Blood pressure is the force of blood pushing against the walls of your arteries. It is written as two numbers: systolic (the top number, when the heart contracts) and diastolic (the bottom number, when it relaxes), measured in millimetres of mercury (mmHg). When pressure stays high, the heart works harder and the arteries are gradually damaged.

According to the World Health Organization, more than a billion adults worldwide have hypertension, and close to half of them are unaware of it. It is one of the leading contributors to heart and circulatory disease.

Approximate clinic readings according to European Society of Cardiology guidance:

For home readings, the threshold for hypertension is lower, usually an average of 135/85 mmHg.

Causes and risk factors

In around nine in ten people there is no single cause; this is primary (essential) hypertension, shaped by genes and lifestyle:

• a high-salt diet, much of it hidden in bread, processed meat, cheese and ready meals;
• being overweight or living with obesity;
• physical inactivity;
• regular alcohol intake;
• smoking, chronic stress and poor sleep;
• age and family history.

In a minority, hypertension is secondary to another condition: chronic kidney disease, narrowing of the kidney arteries, hormonal disorders (such as primary aldosteronism or thyroid disease), sleep apnoea or certain medicines (anti-inflammatory painkillers, decongestants, hormonal contraceptives). Doctors look for a secondary cause particularly in younger people, with very high readings or when blood pressure does not respond to treatment.

Symptoms and complications

Hypertension is often called the "silent killer" because it usually causes no symptoms. Headaches, dizziness, ringing in the ears or nosebleeds can occur but are not reliable signs, so do not rely on how you feel to judge your blood pressure.

Over years, uncontrolled high blood pressure damages so-called target organs:

• the heart – thickening of the heart wall, heart failure, heart attack and atrial fibrillation (see arrhythmias);
• the brain – stroke and vascular dementia;
• the kidneys – chronic kidney disease;
• the eyes – damage to the retina;
• the arteries – atherosclerosis and aortic aneurysm.

How to measure your blood pressure at home

Use a validated automatic upper-arm monitor with a cuff that fits your arm. Wrist monitors are less accurate.

• Sit quietly for five minutes with your back supported, feet flat on the floor and legs uncrossed.
• Rest your arm on a table with the cuff at heart level, on bare skin.
• Avoid smoking, caffeine and exercise for 30 minutes beforehand.
• Take two readings in the morning and two in the evening, one to two minutes apart, for seven days before your appointment.
• Write down all readings and show them to your doctor.

To confirm the diagnosis, your doctor may also arrange 24-hour ambulatory blood pressure monitoring, which also identifies "white-coat" and "masked" hypertension.

Tests after a diagnosis of hypertension

Once hypertension is diagnosed, the usual tests are blood tests (creatinine and eGFR, potassium, sodium, glucose or HbA1c, cholesterol), a urine test for protein, an ECG and, when needed, an echocardiogram. The aim is to estimate your overall cardiovascular risk, detect organ damage and look for secondary causes. These tests are also part of a regular preventive health check-up.

Treatment: lifestyle and medicines

Lifestyle changes are the foundation for everyone with raised blood pressure:

• cutting down on salt by eating fewer processed foods, bread and cured meats;
• a diet rich in vegetables, fruit, pulses and whole grains – see heart-healthy eating;
• losing excess weight;
• regular physical activity, at least 150 minutes of moderate exercise a week;
• limiting alcohol and stopping smoking.

Medicines are started when blood pressure is persistently 140/90 mmHg or higher, or earlier when cardiovascular risk is high. The main classes are ACE inhibitors or angiotensin receptor blockers, calcium channel blockers and thiazide or thiazide-like diuretics; beta-blockers are used for specific reasons. Treatment often starts with two medicines combined in a single pill, which makes it easier to take. If blood pressure stays high despite three medicines at full doses, this is called resistant hypertension, and further medicines are added or renal denervation may be considered at a specialist centre.

ESC guidance suggests a systolic target of 120 to 129 mmHg for most treated people, if tolerated; targets for older and frail people are set individually. Medicines are usually taken long term, often for life, and should not be stopped on your own when readings return to normal.

Special situations: pregnancy, older people and young patients

In pregnancy, high blood pressure needs close monitoring by the obstetric team, as it can be a sign of pre-eclampsia. Some blood pressure medicines (such as ACE inhibitors and angiotensin receptor blockers) are not used in pregnancy, so women planning a pregnancy should discuss their treatment with their doctor in advance.

In older and frail people, blood pressure is lowered more gradually, watching for dizziness on standing and the risk of falls. In younger people with high readings, a secondary cause is looked for more often, and early treatment protects the organs for decades to come.

When to see a doctor

Have your blood pressure checked at least once a year from the age of 40 (more often if you have risk factors), and see your GP if your home readings average 135/85 mmHg or higher. If you are on treatment but readings stay high or you have side effects, discuss changing your medicines.

Call emergency services (112 in the EU) if your blood pressure is very high (for example 180/120 mmHg or above) and you have a severe headache, chest pain, breathlessness, blurred vision, confusion, numbness or weakness on one side of the body, or difficulty speaking. These can be signs of a stroke or another emergency.

Assessment and treatment abroad and in Türkiye

High blood pressure is managed well by your GP and cardiologist at home, and long-term follow-up is best kept close to where you live. Some patients from Bulgaria and across Europe use a stay in Istanbul for a full cardiology assessment at large accredited hospital groups, for example for resistant hypertension, a suspected secondary cause, or when procedures such as renal denervation are being considered. Ask for a written report with all results and recommendations to share with your doctor at home. New City Clinic in Istanbul is a health-tourism organiser that coordinates the hospital, doctor, hotel, transfers and interpreter; medical decisions remain with the treating team.