top of page

Know Your Numbers - What is blood pressure?

Updated: May 16, 2023

We've all felt our blood pressure rise now and again when the stakes are high or frustration gets the better of us. Your GP has probably taken your blood pressure readings numerous times...but do you know what blood pressure really is and what the numbers mean?

Blood pressure is a measure of the force that your heart uses to pump blood around your body.

  • Systolic blood pressure (Top Number) = The highest pressure when your heart beats and pushes the blood round your body.

  • Diastolic blood pressure (Bottom Number) = The lowest pressure when your heart relaxes between beats.

Blood pressure is measured in millimeters of mercury (mmHg).

Low blood pressure

Low blood pressure is also known as hypotension. This is where blood pressure in your arteries is abnormally low.

Naturally low blood pressure is unlikely to cause any symptoms and is normally nothing to worry about. However, if it drops too low, it can restrict the amount of blood flowing to your brain and other vital organs. In turn this can cause unsteadiness, dizziness or fainting.

You can have low blood pressure for many reasons, including the time of day, your age, the temperature, any medication you may be on, an injury, and some illnesses.

Below are some tips to help limit symptoms of low blood pressure:

  • standing up gradually and avoiding standing for long periods of time

  • ensuring you are well hydrated

  • wearing support stockings

  • adding more salt to your diet

  • eating smaller meals more often

High blood pressure

High blood pressure, or hypertension, rarely has noticeable symptoms. But if untreated, it increases your risk of serious problems such as heart attacks and strokes.

The only way to find out if your blood pressure is high is to have your blood pressure checked.

As a general guide:

  • high blood pressure is considered to be 140/90mmHg or higher

  • ideal blood pressure is considered to be between 90/60mmHg and 120/80mmHg

A blood pressure reading between 120/80mmHg and 140/90mmHg could mean you're at risk of developing high blood pressure if you don't take steps to keep your blood pressure under control.

Only one of the numbers has to be higher or lower than it should be to count as either high blood pressure or low blood pressure.

A doctor checking someones blood pressure.
Blood pressure is a measure of the force that your heart uses to pump blood around your body.

Risks of high blood pressure

If your blood pressure is too high, it puts extra strain on your blood vessels, heart and other organs, such as the brain, kidneys and eyes.

Persistent high blood pressure can increase your risk of a number of serious and potentially life-threatening conditions, such as:

If you have high blood pressure, reducing it even a small amount can help lower your risk of these conditions.

Causes of high blood pressure

It's not always clear what causes high blood pressure, but certain things can increase your risk.

You're at an increased risk of high blood pressure if you:

  • Are over the age of 65

  • Are overweight or obese

  • Are of African or Caribbean descent

  • Have a relative with high blood pressure

  • Eat too much salt and don't eat enough fruit and vegetables

  • Lack of exercise

  • Drink too much alcohol or coffee (or other caffeine-based drinks)

  • Smoke

  • Lack of sleep

  • Stress

Making healthy lifestyle changes can help reduce your chances of getting high blood pressure and help lower your blood pressure if it's already high.

Ways to reduce your blood pressure

The following lifestyle changes can help prevent and lower high blood pressure:

  • Reduce the amount of salt you eat and have a generally healthy diet (reduced saturated fat and sugar)

  • Limit alcohol intake

  • Reduce your weight if your overweight/obese

  • Exercise regularly - aim for 30 minutes or more of moderate intensity physical activity every day of the week

  • Cut down on caffeine

  • Stop smoking

  • Try to get at least six hours of sleep a night

  • Take time out to relax

Check your blood pressure

The only way of knowing whether you have high blood pressure is to have a blood pressure test.

All adults over 40 are advised to have their blood pressure checked at least every five years. Getting this done is easy and could save your life. You can get your blood pressure tested at a number of places, including:

  • at your GP surgery

  • at some pharmacies

  • as part of your NHS Health Check

  • in some workplaces

  • You can also check your blood pressure yourself with a home blood pressure monitor and record in a diary.

Click here for an example of an easy blood pressure diary from the British Hypertension Society.

Medicines for high blood pressure

If you're diagnosed with high blood pressure, your doctor may recommend taking one or more medicines to keep it under control.

““Prevention is better than cure, make lifestyle changes today! “
“If you don’t know you blood pressure, its like not knowing the value of your company.”
“More than one in four adults in the UK have high blood pressure, although many won't realise it.”

Our sources & for more information:


Recent Posts

See All



Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

bottom of page