General information about blood pressure
The blood circulation is responsible for supplying the body with oxygen. Blood pressure is the pressure exerted on the arteries when the blood flows through them.
The higher blood pressure value (= systolic pressure or top value) signifies the blood pressure produced by contraction of the heart muscle and subsequent pumping of blood into the arterial system.
The lower blood pressure value (= diastolic pressure or lower value) repre- sents the blood pressure produced by the relaxation phase of the heart muscle, during which blood flows back into the heart.
| Pulmonary (lung) |
| capillaries |
Pulmonary artery | Pulmonary vein |
Vena cava | Aorta |
Right atrium | Left atrium |
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Veins | Arteries |
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Right ventricle | Left ventricle |
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Venules | Arterioles |
| Body capillaries |
Classification of Blood Pressure by the World health Organization
The World Health Organization (WHO) and the International Society of Hypertension (ISH) developed the blood pressure classification shown in the Figure. (This classification is based on the blood pressure values measured by sitting on a chair in the outpatient department of a hospital.)
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Systolic blood pressure
(mmHg) |
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| Severe hypertension |
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180 |
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Moderate hypertension |
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160 |
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Mild hypertension |
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140 |
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Normal systolic value |
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130 |
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Normal blood |
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pressure |
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120 |
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| Diastolic |
Optimal blood |
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pressure |
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| blood |
(target value) |
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| pressure |
80 | 85 | 90 | 100 | 110 | (mmHg) |
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According to the blood pressure classification by the WHO/ISH* (revised in 1999)
*ISH: International Society of Hypertension
*There is no universally accepted definition of hypotension. However, those having the systolic pressure below 100 mmHg are assumed to have hypoten sion.
Health and blood pressure
The incidence of hypertension increases with age. In addition, a lack of exer- cise, excess body fat and high levels of cholesterol (LDL) which sticks to the in- side to blood vessels, reduces elasticity of these vessels. Hypertension accele- rates arterial sclerosis, which can lead to very serious conditions such as stroke and myocardial infarction. For these reasons it is very important to know whether our blood pressure is within a healthy range. Blood pressure fluctuates from minute to minute, throughout the day. Therefore it is essential to take regular readings to help identify an average blood pressure for you.
