Common Characteristics of High Blood Pressure
High blood pressure, or hypertension, is often referred to as "the silent disease" because it has no
symptoms until it reaches an advanced state. Very often, it is detected during a routine doctor's visit
or high blood pressure screening program. Even then, several measurements may be needed to make a
definite diagnosis of hypertension, which is defined as blood pressure that is persistently elevated
over what is considered normal.
Blood pressure is the force that is exerted by the blood against the vessel walls. It is measured by
using a simple instrument called a sphygmomanometer, which consists of an inflatable cuff that goes
around the upper arm and a column of mercury or a pressure dial. When the cuff is inflated, it tightens
around the arm and momentarily blocks the flow of blood through the main artery of the arm. As the cuff
is slowly released, the person taking the blood pressure uses a stethoscope to listen to the returning
blood flow. One sound signals the maximum force that occurs with the heartbeat. This is the systolic
pressure, the higher of the two numbers in a blood pressure reading. The second or lower number, referred
to as the diastolic pressure, reflects the lowest amount of pressure, which occurs between heartbeats.
Everyone's blood pressure varies during the course of a day. As would be expected, it is usually lower
when resting or engaged in quiet activities, and it may spurt up during a sudden burst of activity, such
as running to catch a bus or exercising. Age also affects blood pressure; it is geerally lower in children
and gradually rises as we grow older. Although there is some disagreement over how high is to high,
the average normal blood pressure for healthy children is about 90/60, while the normal adult average ranges
from 100/85 to 135/90. A diastolic pressure over 95 in an otherwise healthy adult is regarded as suspiciously
high and a reading of 140/100 usually would be diagnosed as hypertension that should be treated. Many experts
feel that any diastolic pressure that is consistently over 95 should be treated.
Causes of Hypertension
It is estimated that more than 35 million Americans have hypertension. In the large majority of cases,
the cause of the high pressure is unknown. Doctors refer to this most common form of the disease as primary
or essential hypertension. There are some unusual instances, however, in which the high blood pressure may
be caused by kidney disease, tumor or some other identifiable cause. This is known as secondary hypertension,
and treating the underlying cause usually will cure the high blood pressure.
While the cause of primary hypertension is unknown, a number of factors appear to increase the risk of
developing it. These include a family history of high blood pressure or strokes at an early age, cigarette
smoking, obesity and excessive salt intake. Altering or avoiding these risk factors will not necessarily
prevent hypertension, but all are thought to play some role. Cutting salt intake, stopping smoking or losing
weight may be sufficient to prevent borderline high blood pressure from developing into frank hypertension.
This is particularly true for adolescents or young adults whose blood pressures may be in the higher end of
the normal range.
