What is blood pressure?
Welcome to hypertension-facts.org, your source for answers to frequently asked questions about hypertension and high blood pressure. In these pages you'll find helpful and informative facts about hypertension symptoms, hypertention causes, lowering blood pressure, & more.
Blood Pressure. Blood is carried from the heart to all parts of your body in vessels called arteries. Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats (about 60-70 times a minute at rest), it pumps out blood into the arteries. Your blood pressure is at its highest when the heart beats, pumping the blood. This is called systolic pressure. When the heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure.
- systolic pressure – blood pressure as the heart beats
- diastolic pressure – blood pressure as the heart relaxes between beats
Blood pressure is always given as these two numbers, the systolic and diastolic pressures. Both are important. Usually they are written one above or before the other, such as 120/80 mmHg (millimeters of mercury). The top number is the systolic and the bottom the diastolic. When the two measurements are written down, the systolic pressure is the first or top number, and the diastolic pressure is the second or bottom number (for example, 120/80). If your blood pressure is 120/80, you say that it is "120 over 80." Both numbers in a blood pressure reading are important. As we grow older, systolic blood pressure is especially important.
A third type of blood pressure measurement is the called pulse pressure. Pulse pressure is simply the difference between the systolic and the diastolic readings. Pulse pressure is an indicator of inflammation and stiffness in the arterial walls. The greater pulse pressure, the stiffer and more injured the vessels are thought to be. While pulse pressure is not yet widely used by physicians to determine hypertension treatment, studies indicate that pulse pressure may be a good predictor of cardiovascular problems (i.e. heart problems), particularly in seniors. Some studies suggest that in people over 45 years old, every 10-mm Hg increase in pulse pressure increases the risk for stroke increases by 11%, cardiovascular disease by 10%, and overall mortality by 16%. In younger adults, the risks are even higher.
Blood pressure changes during the day. It is lowest as you sleep and rises when you get up. It also can rise when you are excited, nervous, or active. Still, for most of your waking hours, your blood pressure stays pretty much the same when you are sitting or standing still.
Having high blood pressure or low blood pressure can result in serious medical complications.