Blood pressure

Arteries carry blood away from the heart.

The blood in the arteries is under pressure because of the contractions of the heart muscles. This allows the blood to reach all parts of the body. You can see how the heart pumps the blood to the lungs and rest of the body by studying this animation:

Blood pressure

Blood pressure is measured in millimetres of mercury, mmHg. There are two measurements:

• systolic pressure - the higher measurement when the heart beats, pushing blood through the arteries, and
• diastolic pressure - the lower measurement when the heart rests between beats

A young, fit person may have a blood pressure of about 120 over 70, which means their systolic pressure is 120 mmHg, and their diastolic pressure 70 mmHg.

Blood pressure varies with age. It also varies with lifestyle factors such as:

• diet
• stress
• exercise
• body mass
• alcohol consumption