High Blood Pressure (HBP)

Call emergency services now if a very high blood-pressure reading occurs with chest pain, severe shortness of breath, weakness or numbness, trouble speaking, confusion, fainting, a seizure, sudden severe headache, or a sudden change in vision. If a reading is above 180/120 mmHg without these symptoms, sit quietly and repeat it after at least five minutes. If it remains that high, contact a healthcare professional promptly for same-day advice. Do not take an extra dose unless your prescriber has told you to do so.

What is high blood pressure?

Blood pressure is the force of blood against the artery walls. The systolic number is the pressure when the heart contracts; the diastolic number is the pressure between beats. Persistently raised pressure is called hypertension. It increases the chance of heart attack, stroke, heart failure, kidney disease, vascular disease and cognitive decline, but these outcomes are not inevitable. Detection and sustained treatment substantially reduce risk.

Hypertension is usually silent. Headache, dizziness or nosebleeds are not reliable ways to identify it, so measurement is essential. A single high reading can be affected by pain, anxiety, recent activity, caffeine, nicotine or an unsuitable cuff and does not usually establish a diagnosis.

How blood pressure should be measured

Use a clinically validated upper-arm monitor with the correct cuff size. Before a routine reading, avoid exercise, smoking, caffeine and a large meal for about 30 minutes where practical; empty the bladder and rest quietly for five minutes. Sit with back supported, feet flat and uncrossed, and the bare arm supported at heart level. Do not talk during measurement. Take two readings about one minute apart and record both.

Clinicians should repeat an unexpected clinic reading and check both arms initially. Home or 24-hour ambulatory monitoring can identify white-coat hypertension, in which clinic values are higher, and masked hypertension, in which clinic values appear normal. NICE confirms hypertension when clinic pressure is at least 140/90 mmHg and the daytime ambulatory or home average is at least 135/85 mmHg. Home readings are normally collected for several days according to local instructions.

Why thresholds differ

Guidelines use different labels. WHO, NICE and the European Society of Cardiology generally define clinic hypertension as persistent pressure of at least 140/90 mmHg. The 2025 American guideline calls 130–139 systolic or 80–89 diastolic stage 1 hypertension and 140/90 or above stage 2. These systems are not contradictory: cardiovascular risk rises continuously, and treatment decisions also depend on confirmed averages, age, pregnancy, frailty, diabetes, kidney disease, existing cardiovascular disease and overall risk. Use the thresholds and treatment target agreed with your own healthcare team rather than diagnosing yourself from one number.

Causes and risk factors

Most adults have primary hypertension, which develops through an interaction of age, inherited susceptibility, kidney and hormonal regulation, diet, activity, body composition, alcohol, tobacco, sleep and social or environmental conditions. It is not a personal failing. Unequal access to healthy food, safe activity, medicines and continuing care can affect control.

Secondary hypertension has an identifiable contributor such as kidney disease, obstructive sleep apnoea, thyroid or adrenal disease, pregnancy-related hypertension, or certain medicines and substances. Examples include some anti-inflammatory medicines, decongestants, stimulants, hormonal treatments, liquorice and illicit drugs. Never stop a prescribed medicine without advice. Abrupt onset, very high or resistant pressure, young age, unusual test results or suggestive symptoms may prompt a targeted search for secondary causes.

Assessment after a raised reading

Assessment normally includes repeated accurate measurements, medical and family history, medicine and substance review, examination and cardiovascular-risk discussion. Depending on the setting, tests may include urine albumin and blood, kidney function and electrolytes, glucose or HbA1c, cholesterol and an electrocardiogram. Eye examination or additional heart, kidney, hormone or sleep testing is selected according to findings. Blood pressure arising during pregnancy needs prompt obstetric assessment because thresholds, medicines and emergency signs differ.

Treatment and everyday management

Lifestyle support and prescribed medicines complement one another. A sustainable pattern rich in vegetables, fruit, whole grains, pulses, nuts and appropriate low-fat dairy, with less salt and fewer highly processed foods, can help. Regular physical activity, adequate sleep, tobacco cessation, limiting or avoiding alcohol and gradual weight support where relevant also reduce cardiovascular risk. Potassium-rich food is not safe for everyone, particularly with kidney disease or some medicines, so ask before deliberately increasing potassium or using salt substitutes. Supplements and herbal products are not substitutes for proven care and can interact with treatment.

Medicines are recommended according to the confirmed blood pressure and the person's total risk. Common first-line classes include thiazide-like diuretics, calcium-channel blockers, angiotensin-converting-enzyme inhibitors and angiotensin-receptor blockers. Beta blockers and other classes are useful in selected circumstances. Choice and combinations depend on age, pregnancy potential, kidney function, other conditions, side effects, cost and preference. Do not combine, share, double or stop medicines on your own; sudden interruption can be harmful.

Making the plan workable

Control often takes more than one appointment and sometimes more than one medicine. Ask what each medicine is for, how and when to take it, what side effects need attention, and what to do during illness or missed doses. A pill organizer, reminders, synchronized refills or a once-daily combination may help when appropriate. Tell the team if cost or supply is interrupting treatment; a safer affordable alternative may be available. Family or community support can help if you want it, but measurements and decisions should remain confidential and person-centred.

Stress can temporarily raise a reading and chronic stress may make healthy routines harder, but hypertension is not simply caused by worrying. Relaxation practices can support wellbeing alongside—not instead of—accurate monitoring and clinical care.

Monitoring and outlook

Keep a simple log of readings, time, symptoms and missed doses, and take the monitor to appointments so technique and accuracy can be checked. Your clinician will set an individualized target and follow-up interval. Report dizziness on standing, falls, swelling or other possible side effects rather than abandoning treatment. Resistant readings should trigger confirmation of technique and adherence, review of interacting substances and evaluation for secondary causes before treatment is labelled ineffective.

High blood pressure is usually a long-term condition, but control is achievable. Consistent follow-up, affordable treatment, shared decisions and realistic habits matter more than short-lived restrictions. Even when readings improve, continue the agreed plan until a healthcare professional advises a change.