high blood pressure or hypertension means high pressure (tension) in the arteries. arteries are vessels that carry blood from the pumping heart to all the tissues and organs of the body. high blood pressure does not mean excessive emotional tension although emotional tension and stress can temporarily increase blood pressure. normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called "pre-hypertension" and a blood pressure of 140/90 or above is considered high. the top number which is the systolic blood pressure corresponds to the pressure in the arteries as the heart contracts and pumps blood into the arteries. the bottom number the diastolic pressure represents the pressure in the arteries as the heart relaxes after the contraction. the diastolic pressure reflects the lowest pressure to which the arteries are exposed. an elevation of the systolic and/or diastolic blood pressure increases the risk of developing heart (cardiac) disease kidney (renal) disease hardening of the arteries (atherosclerosis or arteriosclerosis) eye damage and stroke (brain damage). these complications of hypertension are often referred to as end-organ damage because damage to these organs is the end result of chronic (long duration) high blood pressure. for that reason the diagnosis of high blood pressure is important so efforts can be made to normalize blood pressure and prevent complications. it was previously thought that rises in diastolic blood pressure were a more important risk factor than systolic elevations but it is now known that in people 50 years and older systolic hypertension represents a greater risk. affecting approximately one in four adults in the united states hypertension is clearly a major public health problem.
what is high blood pressure?