The full form of mmHg is millimeters of mercury. It is a unit of measurement for pressure, specifically blood pressure.
mmHg is used to measure the force exerted by the blood against the walls of the arteries.
The measurement is based on the height of a column of mercury that is balanced against the pressure being measured.
The higher the pressure, the higher the column of mercury will rise.
While mmHg is a commonly used unit, it is being gradually replaced by the SI unit of pressure, the Pascal (Pa). However, mmHg remains widely used in medical settings due to its familiarity and ease of use.
History and Background
The mmHg unit originated from the invention of the mercury barometer by Evangelista Torricelli in the 17th century. This instrument used mercury to measure atmospheric pressure.
The concept was later adapted to measure blood pressure using a sphygmomanometer, which is a device that measures the pressure of blood flowing through the arteries.
The mmHg unit is still widely used in medical settings because it is familiar to healthcare professionals and patients alike.
Understanding Blood Pressure Measurement
Blood pressure is typically measured in two numbers: systolic and diastolic.
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Systolic pressure is the pressure in the arteries when the heart beats (contracts).
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Diastolic pressure is the pressure in the arteries when the heart rests between beats (relaxes).
A typical blood pressure reading is written as a fraction, with the systolic pressure on top and the diastolic pressure on the bottom. For example, 120/80 mmHg.
Conversion to Other Units
While mmHg is widely used, it is important to understand how to convert it to other units of pressure, particularly the SI unit, Pascal (Pa).
- 1 mmHg = 133.322 Pa
Conclusion
mmHg, or millimeters of mercury, is a unit of pressure commonly used to measure blood pressure. It is a familiar and widely understood unit in medical settings, though its use is gradually being replaced by the SI unit, the Pascal. Understanding the basics of blood pressure measurement, including the difference between systolic and diastolic pressure, is crucial for maintaining good health.
