Normal Blood Pressure Explained

Blood pressure is the force exerted against the wallsNormal resting arterial pressure is a systolic reading
of arteries as blood is flowing through them. As theless than 120 but greater than 90 and a diastolic
heart contracts to delivery more blood into thereading of less than 80 but greater than 60. Although
arteries the force reaches a maximum, known as thethere are trends characteristic of aging these
systolic blood pressure, which is the top number ofnumbers don't change with respect to defining what
the reading. When the heart stops contracting to fillis normal. Hypertension is defined as a systolic
with blood again the pressure within the arteriespressure of 140 or greater and they diastolic blood
recedes to a minimum, which is the diastolic bloodpressure of 90 or greater. This definition of
pressure or the lower number of the reading. When ahypertension was reached by virtue of the fact that
pressure measurement is being taken in either in thestudies have shown that the damage to vessels and
upper arm or the wrist, the measuring device isrelated organs caused by elevated resting arterial
inflated until the pressure generated around thepressure does not begin to occur until pressures
artery exceeds the pressure within the arteryreach these levels. What used to be considered gray
resulting in collapse of the artery. The measuringareas between systolic readings of 120 and 140 and
device is then slowly deflated to the point that thediastolic readings of 80 and 90 are now the ranges
pressure around the artery falls below the pressurethat define what is known as pre-hypertension, i.e.
within the artery while the heart is contracting butreadings between 120/80 and 140/90. The reason
exceeds the pressure in the artery when the heart120/80 is an abnormal reading is that studies have
relaxes, at which point the artery opens when theshown that over time many people with a reading of
heart contracts but collapses when the heart ceased120 or higher will eventually develop hypertension. In
to contract. The audible sound detected at this pointfact, one study showed that virtually 100% of
if the reading is being taken manually or the signalpeople with blood pressure readings of 120/80 will
that is generated from an automated device at thisdevelop hypertension if they live to be 90 years of
point is the collapsing of the artery from is expandedage or more. More realistically, this explains why two
state immediately at the end of contraction of thethirds of the population greater than 65 years of age
heart, which is the systolic blood pressure. As thehas high blood pressure. Low arterial pressure
deflation continues and the pressure around thegenerally is not a concern of most people, but if a
artery continues to drop, a point is reached at whichperson has hypotension, i.e. a systolic reading of 90
the pressure generated around the artery by theor less or a diastolic reading of 60 or less symptoms
device and the pressure within the artery when theof lightheadedness and/or fainting can occur and may
heart relaxes are equal resulting in the artery ceasingbe representative of an underlying disease process in
to collapse and the sound ceasing to be produced.need of evaluation and treatment. Both abnormally
The beginning of this period of silence in which ahigh and abnormally low blood pressure readings need
sound is no longer heard and a signal is no longerto be recognized and appropriately addressed
sensed by an automated device is the diastolic bloodbecause either can be associated with morbidity.
pressure.