High blood pressure is also called hypertension, which refers to a condition in which the blood flow in the arteries of the heart is greatly accelerated. Due to this increase of pressure, the heart needs to work more than normal to maintain blood flow in the blood arteries.
Blood pressure involves two measurements, systolic and diastolic, depending on whether the heart muscle is contracting (systole) or in tension between beats (diastole). Normal blood pressure at rest time is within the range of 100–140 mmHg systolic (highest-reading) and 60–90 mmHg diastolic (lower-reading). Hypertension is present if it persists at or above 90/140 mmHg.