Just What Is Blood Pressure?

Simply put, blood pressure is the force of blood against artery walls. It is measured in millimeters of mercury (mm HG) and recorded as two numbers: systolic (pressure on the arterial walls as the heart contracts) over diastolic (pressure on the arterial walls as the heart relaxes between beats). These two numbers appear as a fraction, with systolic over diastolic (i.e. 120/80). Both numbers are important.

Blood pressure rises and falls during the day. But when it stays elevated over time, then it is called high blood pressure (or hypertension). High blood pressure is dangerous because it makes the heart work too hard, and the force of the blood flow can harm your arteries. This is especially dangerous when coupled with other risks, such as high cholesterol.

High blood pressure often has no warning signs or symptoms. If left uncontrolled, it can lead to heart and kidney disease, heart attack, vision problems and stroke. You may have high blood pressure and not even know it. While 50 million Americans suffer from this affliction, 33 percent don't even know they have it, and 70 percent don't have it under control. Another 45 million are at high risk of developing it.

High blood pressure is a condition without signs or symptoms, which is why it is often referred to as the "silent killer." The only way to know where you stand is to have your blood pressure checked by a qualified professional. You don't have to be one of the millions who live with hypertension and its risks. High blood pressure is easily detectable and usually controllable.