When high blood pressure is an emergency
Go to the emergency department for a very high reading with chest pain, severe breathlessness, confusion, severe headache with visual disturbance, or symptoms of a stroke (face drooping, weakness on one side, slurred speech). In pregnancy, severe headache with vomiting or visual changes needs immediate assessment.
When high blood pressure is an emergency
The situations above. A high number on its own, without symptoms, is not usually an emergency — but it does need proper assessment rather than a repeat reading and a shrug.
The uncomfortable truth about symptoms
There is a widespread belief that high blood pressure causes headaches, nosebleeds, flushing or a feeling of pressure in the head. For the overwhelming majority of people with hypertension, it causes nothing whatsoever.
This matters because the belief is actively harmful in two directions:
- People who feel fine conclude their blood pressure must be fine
- People who feel fine on treatment conclude they no longer need it
Both are among the commonest reasons blood pressure ends up untreated.
Symptoms that do sometimes occur
At genuinely very high levels, or when blood pressure has risen abruptly, some people notice:
- Headache, classically at the back of the head and worse in the morning
- Dizziness or light-headedness
- Blurred vision
- Nosebleeds
- Breathlessness
- Chest discomfort
- Palpitations
None of these is reliable enough to use as a monitoring system. Plenty of people have dangerous readings with none of them, and plenty of people have all of them with normal blood pressure.
What high blood pressure is doing meanwhile
While causing no symptoms, sustained high pressure is:
- Thickening and stiffening arteries, accelerating the fatty deposits that cause heart disease
- Straining the heart, which thickens and eventually pumps less efficiently
- Damaging the kidneys' filtering units — hypertension is a leading cause of kidney failure
- Weakening blood vessels in the brain, which is the mechanism of most strokes
- Damaging small vessels in the eye, visible on examination before you notice anything
This is the entire case for treating a number rather than a feeling.
How to actually know
Have it measured. That is the whole answer, and it takes two minutes.
- If you are over 40 and have not had it checked in the last year, get it checked
- Earlier and more often if you are overweight, have diabetes, smoke, or have a family history of high blood pressure, stroke or kidney disease
- A single high reading is not a diagnosis — blood pressure varies through the day and rises in clinics. It needs repeating on separate occasions
A preventive health checkup includes it alongside blood sugar and cholesterol, which is sensible since they travel together.
Measuring at home properly
Home readings are often more informative than clinic ones. But technique changes the number substantially, so:
- Use a validated upper-arm monitor. Wrist and finger devices are less reliable
- Sit quietly for five minutes first. No tea, coffee or cigarette for 30 minutes before
- Sit with your back supported and feet flat, arm resting at heart level
- Do not talk during the measurement
- Take two or three readings a minute apart and record them all
- Measure at roughly the same times each day, and bring the written record to your appointment
If the numbers are consistently above target, that is information to act on rather than to monitor indefinitely. See hypertension for treatment.
This page is general health information, not medical advice. It cannot account for your history, medication or test results. Please speak to a qualified doctor about your own symptoms and treatment. If you think you are having a medical emergency, seek immediate help.