High blood pressure (hypertension) usually has no obvious symptoms and many people have it without knowing.
Untreated high blood pressure can lead to serious diseases, including stroke, heart disease and kidney failure.
The only way to know if you have high blood pressure is to have your blood pressure measured. All adults should get their blood pressure checked at least once every five years.
In some rare cases, where a person has very high blood pressure, they can experience symptoms, including:
Visit your GP as soon as possible if you find that you have any of these symptoms.
Find out more about who is at risk of high blood pressure.
If you are pregnant, it's important to have your blood pressure checked on a regular basis, even if it isn't high.
Watching your blood pressure while you are pregnant reduces your risk of developing pregnancy-induced hypertension.
This can lead to a serious condition called pre-eclampsia where there is a problem with the placenta (the organ that links the baby’s blood supply to the mother’s).
Read more about antenatal checks and tests.