Blood pressure is the pressure of the blood in the arteries as it is pumped around the body by the heart. According to MacGill of Medical News Today, blood flows through our body because of a difference in pressure. It has “potential”. This is in the same sense of the word as used for another type of flow, that of electricity. “Electrical potential”, or voltage, forces an electrical current through a wire. MacGill further elaborated that our blood pressure is highest at the start of its journey from our heart – when it enters the aorta – and it is lowest at the end of its journey along progressively smaller branches of arteries. Also, while the heart creates the maximum pressure, the properties of the arteries are just as important to maintaining it and allowing blood to flow throughout the body.
Without the elastic nature of the artery walls, for example, the pressure of the blood would fall away more quickly as
it is pumped from the heart. The condition of the arteries has effects on blood pressure and flow, and
narrowing of the arteries can eventually block the supply altogether (a heart attack is the heart itself
being cut off; a stroke is caused when the arteries to the brain are blocked or bleed).
Blood pressure is usually measured by wrapping an inflatable pressure cuff around your
upper arm. There are also other cuffs that can be put around your wrist. Once the cuff is inflated
enough to stop the pulse, a reading is taken, either electronically or on an analog dial. It is then
typically recorder as two numbers written in a ration. The top number is called the systolic pressure,
or the pressure in the arteries when the heart contracts. The bottom number reflects the diastolic
pressure or the pressure in the arteries between heartbeats. This cuff if part of a device called a
sphygmomanometer, which also includes a small pressure gauge. It runs on a simple principle: the
device shows how much pressure is needed before the pulse in our arm stops briefly: the arterial blood
pressure is represented at that point. When taking the blood pressure, the doctor will use a stethoscope
to listen to the blood moving through an artery. The cuff is inflated to a pressure that’s known to
be higher than your systolic blood pressure. As the cuff deflates, the first sound heard through the
stethoscope is the systolic blood pressure. It sounds like a whooshing noise. When this noise goes away,
that indicates the diastolic blood pressure. Blood pressure is measured in millimeters of mercury (mm
Hg). However, the “mm Hg” is not used when reporting the blood pressure.
Blood pressure should be checked, at least once every five years. However, as you get older,
it is better to increase the frequency and have your blood pressure checked more often, as frequently as
suggested by your doctor. The blood pressure is not constant and is usually affected by factors such as
body position, exercise, sleep, breathing and emotional state.