What is blood pressure?
Blood pressure is measured with 2 numbers. Systolic (top) and Diastolic (bottom), Systolic pressure is the force that your heart pumps blood around the body. Diastolic pressure (bottom number) is the resistance to the flow of blood in your blood vessels. Both of these pressures are measured in millimetres of mercury (mmHg).
What is systolic pressure?
The blood pressure when the heart is contracting. It is specifically the maximum arterial pressure during contraction of the left ventricle of the heart. The time at which ventricular contraction occurs is called systole.
In a blood pressure reading, the systolic pressure is typically the first number recorded. For example, with a blood pressure of 120/80 (“120 over 80”), the systolic pressure is 120. By “120” is meant 120 mm Hg (millimetres of mercury).
What is diastolic pressure?
Referring to the time when the heart is in a period of relaxation and dilatation (expansion). The diastolic pressure is specifically the minimum arterial pressure during relaxation and dilatation of the ventricles of the heart when the ventricles fill with blood.
In a blood pressure reading, the diastolic pressure is typically the second number recorded. For example, with a blood pressure of 120/80 (“120 over 80”), the diastolic pressure is 80. By “80” is meant 80 mm Hg (millimetres of mercury).
Sources: NHS, Medicine Net