According to recent research, nearly one in three U.S. adults has high blood pressure, but because there are no symptoms, nearly 1/3 of these people don't know they have it. In fact, many people have high blood pressure for years without knowing it. Uncontrolled high blood pressure can lead to heart attack, stroke, heart failure or kidney failure. This is why high blood pressure is often called the "silent killer." The only way to tell if you have high blood pressure is to have your blood pressure checked.

THE TWO NUMBERS

Blood pressure is divided into two parts, systolic and diastolic. Systolic is the pressure of the heart beating. Diastolic is the pressure of the heart and vessels filling. When blood pressure numbers are written out, like "120/80," 120 is the systolic pressure and 80 is the diastolic pressure. The unit of measurement for blood pressure is millimeters of mercury, written as "mm/Hg."

HEALTHY blood pressure

Experts consider healthy blood pressure numbers to be 115/75 mm/Hg. The reason? They found that the risk of cardiovascular disease doubles at each increment of 20/10 mm/Hg over 115/75 mm/Hg. Even small jumps in blood pressure numbers increase the risk of stroke and heart attack.

A person's blood pressure can naturally vary throughout the day—even between heartbeats. However, if the numbers are consistently high (over 120 systolic and 80 diastolic), after multiple visits to your healthcare practitioner, you may have either pre-hypertension or high blood pressure.