high blood pressure is called hypertension. a person has hypertension if their blood pressure is high and stays high over time. hypertension is very common. about one in every three adults in the united states has high blood pressure. hypertension is sometimes called "the silent killer" because it often causes no symptoms, so many people have high blood pressure without realizing that anything is wrong. however, hypertension can hurt the heart, blood vessels, kidneys, and other parts of the body. it can cause serious health problems like heart attack, stroke, and kidney failure.