Blood pressure is measured by the blood pressure instrument (stethoscope and gauge) and by using the electronic devices.
There are two blood pressure points:
Systolic – When heart contracts and pumps blood in arteries
Diastolic – When heart relaxes and receives blood
The systolic number is the top number on a blood pressure reading. The diastolic number is the bottom number on a blood pressure reading, e.g. 120 / 80 mm of Hg.
Blood pressure varies when we perform different activities. It is absolutely normal, for instance blood pressure increases when we run or excited but comes back to normal when resting. Blood pressure also increases with age and size of the body.