It is often said that the patient’s blood pressure is high or low. However, how could you measure it as high or low? Blood pressure is the pressure created on the arterial wall when the heart pumps. Pressure is the applied force per area. The blood pressure of a person is normally measured by the systolic pressure over the diastolic pressure and is expressed in mm Hg (millimeters of mercury). The normal blood pressure of an adult in resting condition is around 120/80 mm Hg, where 120 mm Hg is the measurement of systolic pressure and 80 mm Hg is diastolic.It is spoken as “one-twenty over eighty”. The range may differ in disease, stress or sleeping condition.
What does it mean by systolic pressure?
It is the maximum pressure in the arteries, exerting by blood. At the end of each cardiac cycle, ventricles contract and throughout the blood to rest of the body. Normal systolic pressure in resting adults is approximately 120 mm Hg. In hypertension, it rises to 140 mm Hg or above and in hypotension, it decreases to around 100 mmHg.
What is diastolic pressure?
At the beginning of a cardiac cycle, the atriums contract and the ventricles become filled with the blood. Atthat time, arteries faced the minimum blood pressure that is known as diastolic pressure. A healthy normal adult has 80 mm Hg diastolic pressure and it differ in disease conditions.
Measurement of blood pressure
The most common tool used for the measurement of blood pressure is a sphygmomanometer. In the past, it had a mercury column, which reflected the circulating blood pressure. Now an electric device indicates the blood pressure instead of mercury, but the standard unit remains same (mm Hg). Different units of pressure are available in mathematics (Pascal, atmosphere), but the blood pressure measuring unit is one for all countries, mm Hg. As the mercury scale was used in sphygmomanometer.
Reference units for blood pressure:
|Health condition||Systolic pressure(mm Hg)||Diastolic pressure(mm Hg)||Systolic/diastolic|
|Normal healthy adult||90-120||60-80||120/80|
The above references are for general population having no other health complications. Health conditions affect the ranges, like nutritional factors, disease, stress, drugs, exercise and mental condition. There are also some factors that affect the blood pressure, they are- pulse rate, body temperature and respiratory rate. Therefore, it is better to monitor your blood pressure in a normal healthy condition and you can check the differences in a diseased state.