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9. Some Useful Information about Blood Pressure
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 this figure.
This classification is based on the blood pressure values measured on 
people in a sitting position in outpatient departments of hospitals.
Note: There is no universally accepted definition of hypotension. 
However, those having the systolic pressure below 100 mmHg 
are assumed as hypotensive.
mmHg
200
150
100
50
61218 24
Example: fluctuation within a day (male, 35 years old)
Time of day
Upper curve: systolic blood pressure
Lower curve: diastolic blood pressure
80
180
160
140
130
120
85 90 100 110
Diastolic 
blood 
pressure 
(mmHg)
Systolic blood pressure 
(mmHg)
Severe hypertension
Moderate hypertension
Mild hypertension
Normal systolic value
Normal blood 
pressure
Optimal blood 
pressure 
(target value)
HEM-7080IT-E.book  Page 48  Monday, April 2, 2007  11:52 AM