Blood pressure is measured in units of millimetres of mercury (mmHg). 2 measurements will be given during a blood pressure measurement:
Systolic pressure (SYS, Upper blood pressure): the pressure when your heart pushes blood out.
Diastolic pressure (DIA, Lower blood pressure): the pressure when your heart rests between beats.
If your blood pressure is 120/80 mmHg (often spoken "120 over 80"), it means you have a systolic pressure of 120mmHg and a diastolic pressure of 80mmHg. The SYS reading is the higher number, whereas the DIA reading is the lower number. Have your blood pressure measured twice, with a brief break in between. If the reading are different by 5 points or more, have it done a third time. The traffic light indicator on Microlife's blood pressure monitors offers you an easy to understand classification based on international hypertension guidelines.