Systolic BP Vs Diastolic BP: Differences Worth Knowing

Blood pressure or BP readings are measured in millimeters of mercury of mmHg and are provided as a pair of numbers. Just citing an example, 110 over 70 is written as 110/70; where 110 is the systolic BP while 70 is the diastolic BP.

Systolic BP Vs Diastolic BP


Let us know more about the differences between the Systolic BP and Diastolic BP

Systolic BP Vs Diastolic BP: Differences worth Knowing

The higher number is the systolic blood pressure or BP reading and it represents the maximum pressure exerted when the heart gets contracted. However the lower number is the diastolic BP reading and it represents the minimum pressure in the arteries when the heart is at relaxed state or at rest.


Below we would look after the differences in a more precise manner.

  1. Systolic BP Vs Diastolic BP: Measuring the Two

    Sphygmomanometer is the instrument used to measure blood pressure. In order to measure the BP, the blood pressure cuff is wrapped around the upper arm snugly, positioning it so that the lower edge of the cuff is 1 inch above the bend of the elbow. The stethoscope head is placed over a large artery then air is pumped in to the cuff until blood circulation is cut off and then air is let out slowly.

    Air is pumped in to the cuff until the blood circulation is cut off. One can notice that there is silence, when a stethoscope is placed over the cuff. Then blood begins to flow again and can be heard via the stethoscope, as the air is slowly let out of the cuff. This is the systolic pressure or the point of greatest pressure and is usually expressed as how high it forces a column of mercury so as to rise in a tube. At its highest normal pressure, the heart sends a column of mercury to a height of about 120 millimeters.

    As more and more air is let out of the cuff, at some point, the pressure exerted by the cuff is so little that the sound of the blood pulsing against the artery walls subsides and then again there is silence. This is the diastolic pressure of the point of lowest pressure, which usually raises the mercury to about 80 millimeters.

  2. Systolic BP Vs Diastolic BP: Differences Based on their Normal Ranges

    Systolic BP measurement in children ranges from 95 to 100 and in adults it ranges from 90 to 120 mmHg. However, the diastolic BP measurement in children is about 65 mmHg.

    Diastolic BP measurements in case of adults; Considering the adults; those who have systolic BP reading less than 90 mmHg and diastolic BP reading less than 60 mmHg, are considered to be suffering from hypotension.

    • Adults having systolic BP reading 121 to 139 mmHg and diastolic BP reading of 81 to 89 mmHg are considered to be at prehypertension state.
    • Adults having systolic BP reading of 140 to 159 mmHg and diastolic BP reading of 90 to 99 mmHg are known to be at stage 1 Hypertension.
    • Adults showing systolic BP reading of 160 mmHg and diastolic BP reading 100 mmHg are known to be at stage 2 Hypertension.
  3. Systolic BP Vs Diastolic BP: Clinical Significance and Cardiovascular Risk

    Earlier, more attention was paid to diastolic pressure; however now it is recognized that both, high systolic BP and high pulse pressure (the numerical difference between systolic BP and diastolic BP) are known to be risk factors. In some cases, it appears that a reduction in excessive diastolic BP can actually increase the cardiovascular risk, probably because of the increased difference between systolic and diastolic pressures.

    Cardiovascular risk in middle-aged and older individuals is more often predicted by using systolic blood pressure measurements than the measurements of diastolic blood pressure. Diastolic blood pressure can be then used for better understanding the risks identified by systolic blood pressure.

  4. Systolic BP Vs Diastolic BP: Differences in Age Factor

    Systolic BP is known to increase with age because of hardening of the arteries. However, diastolic BP readings are particularly important in monitoring the blood pressure in younger individuals.