High blood pressure, why it matters and how it is managed
Hypertension rarely causes symptoms, which is precisely why it needs measuring. How it is diagnosed accurately and treated effectively.
In short
High blood pressure means the pressure in the arteries is persistently raised. It usually causes no symptoms at all, but sustained over years it is a leading cause of stroke, heart attack, heart failure and kidney disease. Diagnosis should not rest on a single clinic reading: readings taken at home or with a 24-hour monitor are more reliable. Treatment combines lifestyle measures with medication where indicated, and the benefit comes from sustained control over years rather than from any single reading.
Call 999 if you have a severe headache with visual disturbance, chest pain, sudden weakness or difficulty speaking. Seek urgent advice if a home reading is 180/120 mmHg or higher, particularly with symptoms.
Key facts
- High blood pressure almost never causes symptoms until damage has already occurred.
- A single raised clinic reading is not a diagnosis; home or 24-hour ambulatory readings are more reliable.
- Readings taken at home are typically lower than clinic readings, and the diagnostic thresholds differ accordingly.
- Most people need more than one medication to reach target, and this is expected rather than a sign of failure.
- Reducing salt, alcohol moderation, weight loss, regular activity and sleep quality all produce measurable reductions.
A risk factor, not a sensation
Blood pressure is recorded as two numbers: the pressure as the heart contracts, and the pressure between beats. Raised readings do not usually produce headaches, nosebleeds or dizziness, and waiting to feel unwell is not a strategy. The reason to treat high blood pressure is that sustained pressure damages arteries silently, and that damage manifests years later as stroke, heart attack, heart failure, kidney disease or vascular dementia.
The relationship is continuous rather than a threshold: the higher the pressure over time, the greater the risk. Treatment targets are set to balance benefit against the burden and side effects of medication.
Measuring it properly
A single reading in a clinic is a poor basis for a diagnosis. Blood pressure varies through the day, with activity and with anxiety, and some people have consistently higher readings in a medical setting than at home.
Where a clinic reading is raised, confirmation should come from either ambulatory monitoring, where a device records readings automatically over 24 hours, or from a structured week of home readings taken twice daily with a validated upper-arm monitor. Because readings at home are typically lower than in clinic, the thresholds used to diagnose and to set targets are correspondingly lower.
Technique matters: seated and rested for five minutes, back supported, arm supported at heart level, correct cuff size, and no caffeine or smoking beforehand.
What else is assessed
Confirmed hypertension prompts a check for damage that has already occurred and for a treatable underlying cause. This usually includes blood tests for kidney function, electrolytes, glucose and cholesterol, a urine test for protein, an ECG, and examination of the retina.
In most people no single cause is found. In a minority there is a specific one, such as kidney disease, a hormonal disorder or obstructive sleep apnoea, and this is more likely where blood pressure is very high, where it appears at a young age, or where it resists several medications. Overall cardiovascular risk is then estimated, because that, rather than the blood pressure figure alone, guides how intensively to treat.
Treatment
Lifestyle measures are not an alternative to medication but work alongside it, and their effects are measurable: reducing salt, moderating alcohol, losing weight where appropriate, regular aerobic activity, stopping smoking, and treating sleep apnoea where present.
Where medication is indicated, the choice of first agent depends on age and background. Most people ultimately need two or three medications from different classes, at moderate doses, rather than one at maximum dose; combining classes is more effective and better tolerated. Reaching target usually takes a few months of adjustment, and requiring more than one tablet is expected rather than a sign that something has gone wrong.
Follow-up
Once control is achieved, review continues periodically with blood pressure readings, kidney function and a reassessment of overall cardiovascular risk. Home monitoring, recorded and brought to appointments, makes those reviews considerably more useful.
Sources
This page provides general information and does not replace individual medical advice, diagnosis or emergency care. Decisions about tests and treatment depend on your own history, examination and results.