Blood pressure is the pressure of the blood against the walls of the arteries.
Blood pressure results from two forces. One is created by the heart as it pumps blood into the arteries and through the circulatory system. The other is the force of the arteries as they resist the blood flow.
What is high blood pressure?
High blood pressure (HBP) or hypertension means high pressure (tension) in the arteries. Arteries are vessels that carry blood from the pumping heart to all the tissues and organs of the body. High blood pressure does not mean excessive emotional tension, although emotional tension and stress can temporarily increase blood pressure. Normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called "pre-hypertension", and a blood pressure of 140/90 or above is considered high.
Cause
Although no specific medical cause can be determined in essential hypertension, it often has several contributing factors. These include
- obesity,[7]
- salt sensitivity
- renin homeostasis insulin resistance
- genetics
- and age.
What is low blood pressure?
Blood pressure is the force exerted by circulating blood on the walls of blood vessels, and constitutes one of the principal vital signs of life, which also include heart beat, rate of breathing, and temperature. Blood pressure is generated by the heart pumping blood into the arteries and is regulated by the response by the arteries to the flow of blood.
Cause
Conditions that reduce the volume of blood, reduce cardiac output (the amount of blood pumped by the heart), and medications are frequent causes of low blood pressure.
- Dehydration
- Moderate or severe bleeding
- Severe inflammation of organs inside the body
Causes of low blood pressure due to heart disease
- Weakened heart muscle
- Pericarditis
- Pulmonary embolism
- A slow heart rate (bradycardia)
- An abnormally fast heart rate (tachycardia)
What do blood pressure numbers indicate?
- The higher (systolic) number represents the pressure while the heart contracts to pump blood to the body.
- The lower (diastolic) number represents the pressure when the heart relaxes between beats.
The systolic pressure is always stated first. For example: 118/76 (118 over 76); systolic = 118, diastolic = 76. Blood pressure below 120 over 80 mmHg (millimeters of mercury) is considered optimal for adults. A systolic pressure of 120 to 139 mmHg or a diastolic pressure of 80 to 89 mmHg is considered "prehypertension" and needs to be watched carefully. A blood pressure reading of 140 over 90 or higher is considered elevated (high).
Categories for Blood Pressure Levels in Adults (in mmHg, or millimeters of mercury)
Category Systolic (top number) Diastolic(bottom number)
Normal Less than 120 And Less than 80
Prehypertension 120–139 Or 80–89
High blood pressure
Stage 1 140–159 Or 90–99
Stage 2 160 or higher Or 100 or higher
Blood Pressure Monitoring
Checking your blood pressure is a simple matter and it is a standard check that will be carried out by your doctor whenever you attend for a routine medical examination. Today, however, there is also an extensive range of relatively inexpensive blood pressure monitors available for home use so that you can now manage your own health with ease in the comfort of your own home.
A blood pressure monitors comes in one of two forms
- an aneroid (manual) monitor
- a digital monitor.
Inflation of digital blood pressure monitors, which come in both arm and wrist models, can be either manual or automatic and deflation is invariably automatic. Units also have very clear readouts and many will keep a record of your readings over time by storing them in the unit's memory. Some will also print out your readings for you and yet others can be attached to a computer so that your readings can be downloaded and analyzed easily with a blood pressure analysis program which comes with the unit.
Site Refference
http://www.americanheart.org/presenter.jhtml?identifier=4473
http://thebloodpressurecenter.com/
http://en.wikipedia.org/
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