The condition puts extra strain on blood vessels and vital organs.
Symptoms of high blood pressure can develop if the condition is extreme. They can include chest pain, severe headaches, difficulty breathing, and a pounding in your chest.
Every adult over 40 years old should get their blood pressure checked at least every five years.
Blood pressure readings have two numbers. The top number is the systolic blood pressure, and the bottom number is the diastolic blood pressure.
Systolic blood pressure is the highest pressure when your heart beats, and pushes blood around the body.
Diastolic blood pressure is the lowest pressure, when the heart relaxes between beats.
“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,” said charity Blood Pressure UK.
If your blood pressure is 90 over 60 (90/60) or less, you may have low blood pressure.
An ideal reading is more than 90 over 60, but less than 120 over 80.
More than 120 over 80, but less than 140 over 90 is a warning sign that you should lower your blood pressure.
Anything over 140 over 90, and you may have high blood pressure.
You should see a GP if you have low blood pressure, or high blood pressure, the NHS said.
Get your blood pressure checked if you keep feeling lightheaded, dizzy, nauseous, or confused.
It could be a sign of low blood pressure, or hypotension.
Diet and lifestyle changes could help to maintain an ideal blood pressure, the NHS said.