The heart is a tough operating mechanism which moves blood around the body through a very advanced system called arteries and capillaries; the blood is then carried back to the heart by means of veins. Blood pressure is the thrust of this blood in the body pushing up against the inside walls of the arteries as the heart is pumping.
As the heart compresses it will drive this blood into the arteries which makes an increase in pressure. This increase in pressure is noted as systolic pressure.
When the heart decompresses and fills with blood, the pressure in the arteries then declines which is noted as the diastolic pressure. When the blood pressure is evaluated in the arm, it is both of these pressures which are evaluated.
Blood pressure is always applied as a systolic and diastolic pressure number, and is an important measurement. The measurements are always written one preceding or before the other number, such as 120/80 and always stated in millimeters of mercury (mmHg).
The systolic pressure is the 1st or top side number, and the diastolic pressure is the 2nd or lowermost number (for example, 120/80), so if your blood pressure is 120/80, it is...