Blood pressure is the amount of force (pressure) that blood exerts on the walls of the blood vessels as it passes through them.
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Blood Pressure Terminology. Blood pressure is reported as a set of two numbers: systolic pressure and diastolic pressure, expressed as “mm Hg, or millimeters of mercury. When the blood pressure is said to be 120 over 80, or 120/80 mm Hg, the first number is the systolic pressure and the second the diastolic. Systolic pressure reflects the force exerted when a person's heart contracts and blood is ejected into the arteries.
http://www.livestrong.com/article/22390-normal-blood-pressure/
The new prehypertension category includes about 45 million men and women who have a systolic blood pressure (the top number) between 120 to 139 mm Hg or a diastolic blood pressure (the bottom number) of 80 to 89 mm Hg.
http://www.webmd.com/hypertension-high-blood-pressure/news/20030514/new-normal-in-high-blood-pressure
The bottom number, called the diastolic pressure, is the measurement as the heart relaxes between beats. Normal blood pressure is a systolic pressure of less than 120 millimeters of mercury (mm Hg) and a diastolic pressure of less than 80 mm Hg, or 120/80 mm Hg, according to the American Heart Association (AHA). Having a blood pressure greater than 140/90 mm Hg is considered high blood pressure or hypertension. A blood pressure level between normal and hypertension, is called prehypertension, meaning it is higher than normal, but not high enough to be considered hypertension.
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The two numbers that measure your blood pressure are written like a fraction: one number on top and one on the bottom. Healthcare providers consider a normal blood pressure reading to be 120/80 or below. However, it can actually fall anywhere in a range from 90/60 to 120/80 -- it's not just one set number. The number on top of the reading is called the systolic pressure. It measures the pressure inside your blood vessels at the moment your heart beats. The number on the bottom is your diastolic pressure. It measures the pressure in your blood vessels between heartbeats, when your heart is resting.
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They also recommend combination treatment using more than one blood pressure drug for people with severe high blood pressure -- blood pressure of 160/100 or higher. It's the first major revision of national blood pressure guidelines since 1997.
http://www.webmd.com/hypertension-high-blood-pressure/news/20030514/new-normal-in-high-blood-pressure
Doctors generally consider a blood pressure of 120/80 mm Hg or less to be normal and healthy. More attention is usually paid to the systolic pressure, but both numbers are important. Either a systolic pressure above 120 or diastolic pressure above 80 may be cause for concern if readings remain consistently high.
http://www.livestrong.com/article/22390-normal-blood-pressure/
Blood pressure reflects the force of blood as it hits the walls of the arteries. When the heart squeezes and pushes the blood out, the blood pushes against the walls of the blood vessels. People are born with very elastic vessels that can expand easily, and bounce back when the pressure on them is low.
http://www.livescience.com/42219-blood-pressure.html
WebMD Health News. May 14, 2003 -- Nearly one in four adults in the U.S. who once thought they had normal blood pressure levels are now considered part of a new risk group category called prehypertension, according to new federal high blood pressure guidelines announced today.
http://www.webmd.com/hypertension-high-blood-pressure/news/20030514/new-normal-in-high-blood-pressure
Chobanian says research has shown that the risk of death due to heart attack and stroke increases rapidly with rising blood pressure levels, starting at levels as low as 115/75 mm Hg. For every 20/10 mm Hg rise in blood pressure above this level, the risk of death from heart problems doubles.
http://www.webmd.com/hypertension-high-blood-pressure/news/20030514/new-normal-in-high-blood-pressure
what is the average blood pressure?
The average blood pressure ranges between 90 by 60 and 120 by 80. The average blood pressure is between 90/60 and 120/80.