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The facts about blood pressure
Q. How does blood pressure work?
A. As your heart beats, it pumps your blood round your body so that your muscles can get all the energy and oxygen they need. To do this, your heart pushes your blood through a network of blood vessels called arteries. As the blood travels through the arteries it pushes against the sides of these blood vessels and the strength of this pushing is called your blood pressure.
As your heart squeezes and pushes your blood through your arteries, your blood pressure goes up. As your heart relaxes, your blood pressure goes down. So, with each heartbeat, your blood pressure will rise to a maximum level and then fall to a minimum level.
When you have your blood pressure taken, the result is given as two numbers - the maximum and minimum levels. This is shown as one number over another, for example:
You would hear this reading said as "110 over 80".The first or top number is the highest level your blood pressure reaches when your heart is squeezing. This is called your systolic blood pressure level. The second or bottom number is the lowest level of your blood pressure when your heart is relaxing. This is called your diastolic pressure.