Table of Contents
Why do we use mmHg to measure pressure?
Because most barometers employ mercury as the liquid (since it is dense and has a low vapor pressure) the height of the liquid is often used as a measure of pressure. Thus millimeters of mercury (mmHg) or centimeters of mercury (cmHg) are sometimes used as units for pressure.
Why do doctors use mmHg?
As mercury is so much denser than water or blood, even very elevated blood pressures result in it rising no more than about a foot. This quirk of medical history gives us the modern measurement unit for blood pressure: millimetres of mercury (mmHg).
What is mmHg used to measure?
Blood pressure is measured in units of millimeters of mercury (mmHg). The readings are always given in pairs, with the upper (systolic) value first, followed by the lower (diastolic) value.
Why is pressure measured in mercury?
Mercury is commonly used in barometers because its high density means the height of the column can be a reasonable size to measure atmospheric pressure. This is because mercury is 13.6 times more dense than water.
What is normal mmHg?
A healthy blood pressure reading should be lower than 120/80 mmHg. Normal blood pressure is less than 120 mmHg systolic and 80 mmHg diastolic (see blood pressure chart below), and may vary from 90/60 mmHg to 120/80 mmHg in a healthy young woman. A blood pressure of 140/90 mmHg or higher indicates high blood pressure.
What does 120 mmHg reading indicate?
What is high blood pressure (hypertension)?
| Blood Pressure Levels | |
|---|---|
| Normal | systolic: less than 120 mm Hg diastolic: less than 80 mm Hg |
| At Risk (prehypertension) | systolic: 120–139 mm Hg diastolic: 80–89 mm Hg |
| High Blood Pressure (hypertension) | systolic: 140 mm Hg or higher diastolic: 90 mm Hg or higher |
What is a normal mmHg?
A normal blood pressure level is less than 120/80 mmHg. No matter your age, you can take steps each day to keep your blood pressure in a healthy range.
IS 30 in Hg high pressure?
A barometer reading of 30 inches (Hg) is considered normal. Strong high pressure could register as high as 30.70 inches, whereas low pressure associated with a hurricane can dip below 27.30 inches (Hurricane Andrew had a measured surface pressure of 27.23 just before its landfall in Miami Dade County).
How do you read mmHg?
When your doctor takes your blood pressure, it’s expressed as a measurement with two numbers, with one number on top (systolic) and one on the bottom (diastolic), like a fraction. For example, 120/80 mm Hg. The top number refers to the amount of pressure in your arteries during the contraction of your heart muscle.
What does mm Hg stand for?
A Manometric Unit of Pressure mmHg stands for millimeters of mercury. mmHg is a manometric unit of pressure, which is almost identical to 1 Torr. In SI units, 1 mmgH = 133.3 Pa.
Does every mmHg really matter?
So every mmHg may matter, but only up to a point, depending on the threshold for that eye. Some evidence indicates that the significance of every mmHg changes depending on the condition of the eye.
Is mmHg and Torr the same thing?
Torr and mmHg are different pressure units but the difference is very low (about 0.000015%) and they are treated as the same pressure unit in most applications. Torr is used in physics and engineering and mmHg is commonly used in measuring the blood pressure.
What does mmHg mean in chemistry?
A measure of force exerted per unit area; in chemistry, most commonly the force exerted by gas molecules as they strike the surfaces around them. Millimeter of Mercury (mmHg) A common unit of pressure referring to the air pressure required to push a column of mercury to a height of 1 mm in a barometer.