Why is high blood pressure silent?
High blood pressure usually has no symptoms and many people who have it do not know. This article explains why measuring is the only way to find out, what the numbers say and when high pressure becomes urgent.
If no one has yet told you that your blood pressure is high, you may think you would certainly have felt it if it were. But that is not so. Both the WHO and the NHS state clearly that high blood pressure usually has no symptoms.
How many people have it and do not know?
The WHO estimates that in 2024 about 1.4 billion adults aged 30 to 79, nearly 33 percent of that age group, had high blood pressure. Of these, about 600 million (44 percent) did not know they had it. Only about 320 million (23 percent) had it under control. The WHO gives the rate in the Eastern Mediterranean region as 38 percent, the highest region.
These are global WHO estimates, not figures for one country or one clinic.
Why is it silent?
High blood pressure means blood hits the walls of the arteries with more force than normal. The body usually does not feel this. The NHS says it may sometimes cause headaches, blurred vision or chest pain, but often it does not. The WHO says the only reliable way to know is to measure it.
Being silent does not mean being harmless. The NHS says high pressure strains the arteries, heart, brain, kidneys and eyes, and if untreated raises the risk of heart disease, heart attack, stroke, heart failure, kidney disease and vascular dementia. The WHO says uncontrolled high pressure is one of the main causes of early death in the world. The NHS also stresses that even a small reduction in blood pressure lowers these risks.
Who should measure?
The NHS says to have it measured if you think your pressure is high, or if you are 40 or older and have not had it checked for more than five years. The NHS and the WHO give these as risk factors:
- Older age (WHO: over 65)
- A close relative with high blood pressure
- A salty and unhealthy diet, being overweight, not being active
- Smoking and heavy alcohol
- Long-term stress
- Diabetes and kidney disease (WHO)
What do the numbers say?
The NHS says high blood pressure usually means 140/90 or more when measured by a healthcare professional, or 135/85 or more at home. The WHO requires 140/90 or more on two different days for a diagnosis. So one high number alone is not a diagnosis. A few days of measuring at home, another check after a few days or weeks, or a 24-hour monitor may be needed (NHS).
Read the guide “Measuring blood pressure at home” for the correct way to measure at home.
After a diagnosis
The basis of treatment is lifestyle change. The WHO and the NHS stress: a balanced, low-salt diet, regular activity (WHO: 150 minutes a week of moderate aerobic activity, or 75 minutes of vigorous), losing weight if overweight, stopping smoking and cutting down on alcohol. The WHO gives less than 2 grams of salt a day.
Some people also need medicine. The NHS says a doctor usually prescribes medicine when the pressure is very high, the risk of heart attack or stroke is higher, or it is still high despite lifestyle changes. Take medicines as directed and do not stop or cut down on your own (WHO).
When does high pressure become urgent?
Although high pressure is usually silent, when it goes very high it may give signs. The WHO says very high pressure, usually 180/120 or more, can cause a severe headache, chest pain, dizziness, breathlessness, nausea, vomiting, changes in vision, confusion, ringing in the ears, nosebleeds or an irregular heartbeat, and needs urgent care.
Call 115 (Iran’s emergency number) if the reading is very high and you have any of these signs, or if you have sudden chest pain, severe breathlessness, sudden weakness on one side of the face or body, or trouble speaking. Do not drive yourself.
Symptoms and treatment plans differ from patient to patient. Talk to a doctor about your own situation.