The force that drives blood flow in the body is called blood pressure. We need to maintain normal blood pressure levels in the circulatory system in order to deliver oxygen and nutrients in the blood to the various organs and tissues.

If your blood pressure is too high or too low, blood circulation will be impaired, and this will result in failure to distribute oxygen and important nutrients to the body. Immune system function may also be compromised because white blood cells cannot be distributed.

Here we offer a brief explanation about blood pressure measurement and what normal, high or low readings mean.

Importance of Blood Pressure

The circulatory system functions to move blood around the body through a force called blood pressure. This life force is important because it provides a means to distribute oxygen and nutrients to the different parts of the body. Also, it aids in the distribution of hormones such as insulin, immune cells and antibodies throughout the body. In addition, the blood also helps clear the toxins and waste products such as carbon dioxide out of our liver, kidneys, and other parts of our body.

How Is Blood Pressure Measured?

Healthcare providers, such as doctors and nurses, measure your blood pressure using an instrument called a sphygmomanometer. This monitor has a cuff, a pressure gauge, a pump and a valve. It is used this way:

• A properly fitting cuff is wrapped snugly around the upper arm.
• The cuff is inflated by squeezing the pump against a closed valve, which results in stopping the blood flow to your arm for a brief period.
• The end (diaphragm) of a stethoscope is placed on the arm near the cuff, in the inner surface of the elbow.
• The valve is slowly opened to release air from the arm cuff, and blood flow begins through the arm, causing a pulsating sound, which is heard over the ear piece of the stethoscope.
• The first pulse sound heard over the number found in the pressure gauge is recorded as the systolic blood pressure, which represents the pressure in the artery when the heart beats.
• The sound fades and disappears, and the number on the pressure gauge over which this occurs is recorded as the diastolic blood pressure. This represents the pressure in your artery between beats when the heart rests.
• The two numbers that represent your blood pressure are written as a fraction. The number on top is the systolic blood pressure, while the number at the bottom is the diastolic blood pressure. So, if your blood pressure (BP) is 120/70, your systolic BP is 120 and your diastolic BP is 70. These readings are expressed in millimeters mercury (mm Hg).
• The healthcare provider may take two or more readings to verify the results, and an average reading may be recorded.

How to Prepare for Blood Pressure Measurement

Below are several things you should know before measuring your blood pressure:

• Sit down for about 5 minutes before the procedure.
• Blood pressure measurements may not be accurate if you are stressed, have had coffee or smoked 30 minutes before measurement, or have just exercised.
• Take 2-3 BP readings per sitting. Set each reading in one or two minutes apart.
• Take blood pressure readings in the morning and at night for about a week and record them. This can help your doctor with his assessment and decision for your treatment.

Understand the Results of Blood Pressure Measurement

Blood pressure measurement consists of two numbers. The number on top is the systolic blood pressure. It indicates the pressure in the blood vessels when your heart beats. The number below is the diastolic blood pressure, and it indicates the pressure in your blood vessels when your heart is at rest between beats.

A blood pressure reading of 110/80 mm Hg (says 110 over 80) means that 110 is the systolic pressure and 80 is the diastolic pressure.

The chart below illustrates what a normal blood pressure, at-risk (prehypertension), and high blood pressure are. If your blood pressure is less than 120/80 mmHg, it is considered normal. On the other hand, if it is more than 140/90 mmHg, it is considered too high. Blood pressure levels between 120/80 and 140/90 indicates you are at risk for developing high blood pressure (prehypertension).

Blood Pressure Levels
Category	Systolic	Diastolic
Normal	less than 120 mmHg	less than 80 mmHg
Prehypertension (at risk)	120–139 mmHg	80-90 mmHg
Hypertension	140 mmHg or higher	90 mmHg or higher

Watch this video to learn how to monitor your blood pressure at home: