Blood pressure is the pressure or force exerted on the arteries by the blood as it flows or travels through them. It is usually measured in millimeters of mercury (mmHg) with the aid of a sphygmomanometer.
Two readings are important and should be noted while taking blood pressure measurement: they are the systolic and the diastolic pressure. Systolic is the pressure produced when the heart contracts, while diastolic is the pressure produced when the heart is at rest, and as the ventricles dilate and are refilled with blood. Systolic is therefore the upper reading while diastolic is the lower reading.
The normal range of blood pressure readings for a young adult is 100-120/70-80mmHg, though this may vary with age. Sometimes the formula 100±20/70±10 could be used to determine the normal pressure for a young adult.
How is it measured?
Usually the individual is made to sit down for at least 2-3 minutes before readings are taken. The cuff of the sphygmomanometer (Analogue or digital) is wrapped around his upper arm (whichever arm you choose) with the bottom of the cuff about ½” above your elbow. Place the earpiece of your stethoscope on your ears and place the diaphragm over the brachial artery (at the inside of the elbow) and inflate, Listening as you inflate (if using the analogue sphygmomanometer). Take the upper reading where you start to hear the heart beat and then the lower reading where the beating stops and record them. If the upper reading is heard at 120 and the lower at 70, the blood pressure is then 120/70mmHg. If you are using the digital sphygmomanometer, follow same procedure but without using the stethoscope. Press the button and the cuff is inflated automatically. The readings are displayed on the monitor, including the pulse rate.
Note that some factors affect the blood pressure. Some of the factors include Age, Drugs, Exercise, Position, body surface etc. For instance blood pressure slightly increases with age and in a person with a larger body surface.
Some terminologies you should know:
1. Normotension: this refers to normal blood pressure. It is the ideal for an individual, depending on his or her age.
2. High blood pressure: this is when the blood pressure is elevated above normal. Normally it is elevated above 140/90mmHg.
3. Hypertension: this is the persistent elevation of blood pressure above 140/90mmHg.
4. Hypotension: It is an abnormally low arterial blood pressure. This could be a reading of below 80/60mmHg.
An abnormally high blood pressure is dangerous just as an abnormally low one is. There should therefore be a balance. The best desired blood pressures should then be the normotensive pressure.
