When the ventricles in the heart contract, it is termed as a systolic activity, while the relaxing ventricles mark a diastolic activity.
The pressure of blood is highest during the systole activity and lowest during the diastole activity. The unit of measuring blood pressure is millimeters. A normal blood pressure reading is 120/80 mmHg.
A normal healthy person maintains the blood pressure reading of 120/80 mmHg. A deviation from this normal reading can result in a blood pressure disorder. There are basically two abnormal conditions of blood pressure. They are known as high blood pressure or hypertension and low blood pressure or hypotension.

