In your body, it’s the force with which blood flows through your arteries, the blood vessels that carry blood from your heart to the rest of your body.

It’s helpful to think of blood pressure like the force of water flowing through a hose.

Blood pressure is measured using two numbers:

• Systolic pressure: this is the higher of the two numbers. It’s the pressure against your arteries when your heart is pumping blood around your body.
• Diastolic pressure: this is the lower of the two numbers. It shows how much pressure is in your arteries when your heart relaxes between beats.

They're both measured in millimetres of mercury (mmHg).

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 health conditions, such as:

• heart disease
• heart attacks
• strokes
• heart failure
• peripheral arterial disease
• aortic aneurysms
• kidney disease
• vascular dementia

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

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

You might be more at risk if you:

• are overweight
• eat too much salt and do not eat enough fruit and vegetables
• do not do enough exercise
• drink too much alcohol or coffee (or other caffeine-based drinks)
• smoke
• have a lot of stress
• are over 65 years old
• have a relative with high blood pressure
• are of black African or Black Caribbean descent
• live in a deprived area

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

High blood pressure is also sometimes caused by an underlying health condition or taking a certain medicine.

Most people don't know they have high blood pressure because there aren't obvious symptoms.

In rare cases, it can cause symptoms like blurred vision, headaches and nosebleeds.

However, it is estimated that 40,000 people in Somerset with high blood pressure who do not know they have it.

That's why it's so important to get your blood pressure checked regularly.

Your blood pressure will usually need to be checked more than once to confirm a diagnosis of high blood pressure.

This is because blood pressure can go up and down a lot during the day. When people have their blood pressure checked in a clinic, or medical setting, it can be higher than expected, especially if they feel nervous or anxious.

If you're monitoring your blood pressure yourself using a home monitor then you should check your blood pressure over several days. This can include taking a series of recordings (at least two), twice a day, in the morning and evening.

By looking at all your blood pressure readings over a few days, a healthcare professional can work out what your 'average’ blood pressure is.

Low blood pressure is a reading of less than 90/60mmHg. It is not usually a problem, as blood pressure can be naturally low for some people. However, sometimes it can be caused by illness, a health condition, or some medications.

Symptoms of low blood pressure:

Get your blood pressure checked if you keep getting symptoms like:

• lightheadedness or dizziness
• feeling sick
• blurred vision
• generally feeling weak
• confusion
• fainting

This might indicate that your blood pressure is too low.

If you get symptoms when you stand up or suddenly change position, you may have a type of low blood pressure called postural hypotension.

If you get symptoms such as dizziness and fainting, please call 111.

If you’re having symptoms, you should check your blood pressure every month or as often as your doctor advises.

However, if you feel well, you should check your blood pressure at home again in 1 year. You should also have your blood pressure checked at a GP surgery or pharmacy at least once every 5 years.

Things you can do to help with low blood pressure symptoms

• get up slowly from lying to sitting to standing
• eat small, frequent meals
• increase the amount of water you drink
• ask your doctor to review your medicines