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What is High Blood Pressure? High
blood pressure or hypertension is high pressure (tension) in the
arteries. The arteries are the vessels that carry blood from the
pumping heart to all of the tissues and organs of the body. High
blood pressure does not mean excessive emotional tension, although
emotional tension and stress
can temporarily increase the blood pressure. Normal blood pressure is
below 120/80; blood pressure between 120/80 and 139/89 is called
“pre-hypertension”, and a blood pressure of 140/90 or above is
considered high blood pressure. The systolic blood pressure, which is
the top number, represents the pressure in the arteries as the heart
contracts and pumps blood into the arteries. The diastolic
pressure, which is the bottom number, represents the pressure in the
arteries as the heart relaxes after the contraction. The diastolic
pressure, therefore, reflects the minimum pressure to which the
arteries are exposed.
Blood
pressure is the force in the arteries when the heart beats (systolic
pressure) and when the heart is at rest (diastolic pressure).
It's measured in millimetres of mercury (mm Hg). High blood pressure
(or hypertension)
is defined in an adult as a blood pressure greater than or equal to
140 mm Hg systolic pressure or greater than or equal to 90 mm Hg
diastolic pressure.
High blood pressure
directly increases the risk of coronary heart disease (which leads to
heart attack) and stroke, especially when it's present with
other risk factors.
High blood pressure can
occur in children or adults, but it's more common among people over
age 35. It's particularly prevalent in African Americans, middle-aged
and elderly people, obese people, heavy drinkers and women who are
taking birth control pills. It may run in families, but many people
with a strong family history of high blood pressure never have it.
People with diabetes mellitus, gout or kidney disease are more likely
to have high blood pressure, too. (American Heart Association).
An
elevation of the systolic and/or diastolic blood pressure increases
the risk of developing heart (cardiac) disease, kidney (renal)
disease, hardening of the arteries (atherosclerosis or
arteriosclerosis), eye damage, and stroke
(brain damage). These complications of hypertension are often
referred to as end-organ damage because damage to these organs is the
end result of chronic (long duration) high blood pressure.
Accordingly, the diagnosis of high blood pressure in an individual is
important so that efforts can be made to normalize the blood pressure
and, thereby, prevent the complications. Since hypertension affects
approximately 1 in 4 adults in the United States, it is clearly a
major public health problem.
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