WHAT IS HIGH BLOOD PRESSURE?

High blood pressure (also called hypertension) is diagnosed when a patient’s blood is pushing too hard against the walls of the arteries. High blood pressure is a dangerous condition that is linked to heart attack, heart failure, stroke, kidney disease and other disorders.

Generally, high blood pressure is classified according to its cause. High blood pressure that has no known cause is called primary, or essential. Between 90 and 95 percent of cases of high blood pressure are primary.

High blood pressure that is caused by another disease or condition is known as secondary hypertension. For instance, renovascular hypertension is caused by kidney disease. There are also a number of other terms physicians use to describe high blood pressure, including malignant and labile. White coat hypertension is high blood pressure that only occurs in a physician's office, usually in response to stress associated with the test itself. 

High blood pressure is measured according to the cycle of the heart. The peak pressure, taken during the contraction phase of the heart, is known as systolic pressure. The lowest pressure, taken during the relaxation phase of the heart’s pumping action, is called the diastolic pressure. Blood pressure is expressed as systolic pressure over diastolic pressure (e.g., 120 millimeters of mercury (mmHg) over 80 mmHg). Each of these measurements is helpful to determine what kind of blood pressure might be present and how to best treat it.