Blood pressure is one of the major vital signs used to assess a person's general health. It refers to the pressure that is exerted by the blood on the walls of the blood vessels as it circulates throughout the body. A measurement of blood pressure is typically given in two numbers. The first number refers to the systolic pressure, which is the maximum pressure exerted during each heartbeat. The second number gives the diastolic pressure, which is the minimum pressure during each heartbeat. Both numbers are expressed in millimeters of mercury, abbreviated as "mmHg." Blood pressure is typically measured with the use of a cuff on the upper arm that is attached to a sphygmomanometer.
For a healthy adult, systolic blood pressure should fall between 90 and 119, and diastolic pressure should fall between 60 and 79. Blood pressure that is too low to fall into these ranges is described as hypo tension. Low blood pressure is not necessarily a sign of any disorder, though it is often a symptom of shock. While for some people, low blood pressure is a sign of fitness, in others it is a sign of some physical problem. Blood pressure that remains low for too long can cause fainting or more serious problems by limiting the supply of blood to the brain and other vital organs.
Systolic blood pressure that is above 120 and diastolic pressure that is above 80 indicates pre hypertension, or high blood pressure. Once blood pressure is above 140/90, it indicates full hypertension. Hypertension is a significant risk factor for a number of different medical conditions of varying severity, including strokes, heart attacks, aneurysms and kidney disease. In many cases, changes in diet or increased exercise can reduce high blood pressure, though for many patients prescription drugs are needed to bring their blood pressure down to an acceptable level.