Blood Pressure Info
A person's blood pressure reading is a measurement of the pressure inside blood vessels, both while the heart is beating and while it is at rest. A special device called a sphygmomanometer is used to take this reading, which is written as a fraction -- for example: 120/80.
In order to determine if your blood pressure is normal or too high, several different readings are taken over a period of time and the average is considered your "normal" blood pressure. Various factors can affect this, such as whether you are standing or lying down and whether you use tobacco products.
(Click Blood Pressure for more info, including what is considered a normal reading and what is considered too high, as well as the role of blood vessels in the body.)