Your blood pressure is the force of blood pushing against your blood vessel walls. When you have high blood pressure, the pressure in your arteries is elevated. One in four adults, about 50 million Americans, have high blood pressure. When untreated, it can increase the risk of heart attack and stroke.
High blood pressure usually has no symptoms, so it is often called the "silent killer." The only way to tell if you have high blood pressure is to get it checked regularly. The Red Cross checks your blood pressure before every donation!