- Diseases, Disorders & Conditions
Systolic and Diastolic Blood Pressure and Pulse (with relationship) and measuring blood pressure with instruments (chart
Measuring blood pressure
The blood pressure is measured by attaching a sphygmomanometer, an inflatable cuff, to a pressure gauge, most commonly to the upper arm. The cuff is wrapped around the upper arm and is inflated until the pressure in the cuff exerts the blood pressure. Therefore, there is no blood going through the artery (upper arm) and the forearm is not supplied with blood. By using a stethoscope, one can hear the blood pulsing. If the cuff has a higher pressure than the artery, there will be no sound (no pulse) below the cuff (because there is no “new” blood flowing into the forearm, since the artery is closed). The cuff is gradually deflated and so; one can hear a sound (pulse of blood) with a stethoscope. This occurs when the blood pressure of the artery is greater than the pressure of the cuff, logically. The pressure at this point is called the systolic pressure (maximum pressure of blood).
The cuff is loosened further until the blood can flow freely through the artery (pressure of the cuff is zero) and the sounds below the cuff will disappear. The pressure at this point is called the diastolic pressure (minimum pressure of blood).
Difference between pulse and blood pressure
Pulse: The rate of how often the heart actually beats in one minute. The vessels are constricted and this type of pressure is called “systolic pressure”.
Blood pressure: The amplitude of blood that is exerted on the walls of the arteries. The vessels are in a relaxed state and this type of pressure is called “diastolic pressure”.
Interpretation of results (blood pressure chart)
For the interpretation of the results, please look at the picture.
The first number is the systolic pressure and the second the diastolic pressure. The normal blood pressure of an adult is usually about 120/80 (say: one-twenty over eighty). So, an adult has 120 heart beats per minute and the amplitude of the blood pressure exerted on the walls of the vessels is 80.