Diagnosing high blood pressure
High blood pressure, also called hypertension, affects around 30% of people in England. However, many people don’t know they have it because it doesn’t usually cause any obvious symptoms, gaining it the nickname the ‘silent killer’.
Untreated, high blood pressure increases a person's risk of having a heart attack or stroke. That's why all healthy adults over 40 should have their blood pressure checked at least every 5 years.
People with heart conditions, kidney problems or other risk factors, such as diabetes, will have their blood pressure monitored more often as part of their overall care.
Measuring blood pressure
You can get your blood pressure measured by your GP or practice nurse, at most pharmacies, or you can buy a blood pressure monitor to use at home.
Blood pressure is usually measured with an electronic device with an automatically inflating arm cuff, but some doctors and nurses still prefer the old fashioned aneroid sphygmomanometer, which consists of using a stethoscope, arm cuff, dial, pump and valve.
A person should rest for at least 5 minutes and have an empty bladder before having their blood pressure tested.
For accurate reading, the person should also be sitting down and not talking during the reading.
Blood pressure numbers
Blood pressure is described with two numbers: systolic and diastolic.
Systolic blood pressure is the pressure during a heartbeat.
Diastolic blood pressure is the pressure between heartbeats.
Blood pressure is measured in millimetres of mercury (mm Hg) and is written systolic over diastolic (for example 120/80 mm Hg, or ‘120 over 80’).
Blood pressure may increase or decrease, depending on your age, heart condition, emotions, activity and the medication you take. Readings for the same person can differ during the day.
One high reading does not mean you will be diagnosed as having high blood pressure.
High blood pressure is diagnosed when the readings on separate occasions are consistently above 140/90.
For those with heart or circulatory disease, diabetes or kidney disease blood pressure should be below 130/80.
Questions for your doctor or nurse about hypertension
If you are still unsure what your blood pressure readings mean, don't leave the surgery or clinic without asking for an explanation and more information.
If your systolic (top reading) is 180 or above, you may be offered medicines to help lower your blood pressure.
Ask about lifestyle tips on diet and exercise and how they can help deliver better blood pressure readings and protect your health.
NHS guidelines say that if your blood pressure is 140/90 or above, your doctor should offer to check your risk of cardiovascular (heart and circulation) disease and check the health of your heart, kidneys and eyes.
They may also offer to test your blood pressure away from the surgery or clinic to make sure the readings are accurate, and not high because of the stress of seeing a doctor. Even though GPs tend not to wear white coats, this is known as "white coat syndrome". Checking blood pressure at home or on the move (ambulatory blood pressure monitoring) was introduced into NHS guidelines in 2011.