The Facts
Heart disease is one of the leading causes of death worldwide, and people who have abnormally high pressure in their arteries are far more likely than others to die prematurely of heart disease.
Your arteries carry the blood from your heart throughout your body. Blood pressure is the measure of how hard your blood is pushing against the inside of your arteries. Although a certain amount of pressure is needed to carry the blood through your body, if that pressure is too great, you have high blood pressure, or hypertension.
When blood pressure is measured, there are two numbers for each reading: for example, "one-twenty over eighty," written as 120/80. This is because each heartbeat sends a pressure wave through the bloodstream. The higher figure (systolic blood pressure) is the peak of the wave, when your heart contracts (the loud "thump" when you listen to your heartbeat). The lower figure (diastolic blood pressure) is the lower "dip" or trough of the wave, when your heart relaxes.
Blood pressure is always recorded as the systolic number over the diastolic number; the numbers indicate pressure as measured in millimeters of mercury on the gauge (mm Hg). In general, someone has high blood pressure if several measurements of blood pressure at the doctor's office show readings above 140 systolic or 90 diastolic.
Hypertension is one of the main risk factors for heart disease, stroke, and kidney failure. In the United States, 31% of adults have high blood pressure. Many are not aware of the problem. Only 70% of those who take medication for hypertension receive adequate treatment to control their blood pressure.