Hypertension and blood pressure measuring

Hypertension or high blood pressure is another circulatory disorder increasingly affecting people around the world.  To understand the condition it is useful to know about the mechanism behind.
Our heart pumps blood to every cell of the body. Contraction of the heart walls provide the pressure required to reach the peripheral tissues. The systolic blood pressure is the maximum pressure a heart produce to pump blood to the body and lung. The diastolic pressure is the blood pressure during the relaxing phase of the cardiac cycle and it is the minimum. A healthy adult have a systolic pressure between 90-140hgmm and diastolic pressure between 60-90hgmm. Significant deviation from the normal ranges poses a health risk.
If the blood pressure increases above the normal levels the end organs such as, liver, kidneys, brain cells, eyes can be damaged. If it drops, it also can cause a problem due to poor blood supply.
Hypertension categories (WHO)
                                                Systolic           and/or  Diastolic

Optimal                                       <120                            <80

Normal                                      120-129                       80-84
Higher normal                            130-139                       85-89
Mild hypertension                      140-159                       90-99
Moderate hypertension              160-180                       100-109
Severe hypertension                   160>                            100>