Blood pressure, as most of us know, is designated by two numbers. Example as-120/80 The top number (120) or the systolic blood pressure (SBP) is the pressure in the blood vessels while the main pumping chamber of the heart is squeezing. This is dependent upon the volume of blood being ejected, the diameter of the blood vessels, the elasticity (or stiffness) of these blood vessels. The bottom number(80) or the diastolic blood pressure (DBP) is the pressure in these blood vessels while the pumping chamber of the heart is relaxing and is mainly dependent on the elasticity (or resilience) of the blood vessels. This seemingly simple explanation is however dependent on a complex interplay of a variety of chemicals in the body known in medical jargon as neurohumoral mechanism.
Why should there be blood pressure?
While pressure in the blood vessels is vital to bring blood to the various organs of the body, high blood pressure (hypertension) can cause over the course of time, damage to both the blood vessels and the various organs. This leads to premature aging of the blood vessels and organs leading to heart attack, stroke, kidney failure and poor circulation. Unfortunately most cases of hypertension are without symptoms and hence may be unrecognized and untreated thus lurking as a silent killer.
How is Hypertension classified?
Present guidelines classify blood pressure as noted below. The higher the blood pressure is over the normal limits, the greater is the risk of disease resulting from it.
Normal blood pressure: SBP < 120 and DBP< 80
Prehypertension: SBP 120 to 139 and/ or DBP 80 to 89
Hypertension: SBP > 140 and/ or DBP > 90