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BASIC FACTS
Hypertension is high blood pressure that persists over time.
More Americans visit their physician for the management of
hypertension than for any other disease-specific reason.
Compared to people with normal blood pressure, people with
hypertension are three times more likely to develop coronary
heart disease, six times more likely to develop congestive
heart failure, and seven times more likely to have a stroke.
Blood pressure is the outward pressure that blood exerts on
the walls of the arteries as it flows through them. This outward
pressure is determined by how much blood the heart pumps and the
resistance of artery walls to the blood. Blood that enters and
flows through arteries easily results in normal blood pressure.
When the heart faces resistance and it must work harder to pump
blood through the body, high blood pressure results. Hypertension
is high blood pressure that persists over time.
As blood is pumped from the heart to the body, the force it
exerts against the walls of the arteries is called blood pressure.
A blood pressure reading uses two numbers that represent the
two phases of the heartbeat. The systolic reading corresponds
to blood pressure when the heart contracts; the diastolic
reading corresponds to blood pressure when the heart relaxes.
Normal blood pressure is less than 130 millimeters of mercury,
(mm Hg) systolic and less than 85 mm Hg diastolic, expressed
as 130 over 85 (for example 130/85). A person has hypertension
if his or her blood pressure is consistently 140 over 90 mm Hg
or higher.
Hypertension can accelerate atherosclerosis, or hardening of
arteries, because arteries that carry blood under high pressures
thicken, and arteries thickened from hypertension are more
susceptible to atherosclerosis. Because hypertension affects
the arterial system in this way, it can contribute to various
conditions, including:
- Heart attack;
- Stroke;
- Kidney failure;
- Coronary heart disease;
- Congestive heart failure;
- Cardiomyopathy;
- Angina pectoris; and
- Blurred vision and blindness.
WHAT ARE THE SYMPTOMS?
Most people with hypertension initially have no symptoms. When
symptoms occur, they can include:
- Headache;
- Nosebleeds;
- Fatigue;
- Dizziness; and
- Flushed face.
Left untreated, the symptoms of severe hypertension
can advance to include:
- Nausea;
- Irregular or rapid heartbeat;
- Vomiting;
- Shortness of breath;
- Blurred vision; and
- A buzzing noise inside the head.
CAUSES AND RISK FACTORS
Most often, when the cause of hypertension is unknown, it is
called primary, or essential, hypertension. Secondary hypertension
is high blood pressure caused by another condition (such as kidney
problems, adrenal gland disorders, narrowing of the aorta, or
pregnancy). Some potential causes of primary hypertension include:
- Narrowed arteries;
- Excessive blood volume; and
- An abnormally faster or forceful heartbeat.
Several risk factors influence the development of hypertension,
including:
- Age (The risk of developing hypertension increases after age 35; 65 percent of people older than 60 have hypertension.);
- Heredity;
- Race (African Americans are more likely to develop hypertension than Caucasians.);
- Gender (Until age 55, men are more likely to develop hypertension than women. Women become more likely to develop hypertension with age, however.);
- Smoking;
- Being overweight;
- Alcohol;
- Sedentary lifestyle; and
- Medications.
DIAGNOSIS
Blood pressure normally fluctuates. Therefore, hypertension is only
diagnosed if blood pressure is consistently high over time.
A physician measures blood pressure using a device called a sphygmomanometer,
which is attached to an armband-like cuff that is wrapped snugly around the
upper arm. The cuff is inflated so that it momentarily blocks blood flow.
The physician then slowly releases the air from the cuff, resuming blood
flow, and listens to the sounds of blood flowing to the artery while
watching the dial on the sphygmomanometer. The position of the dial during
the first audible thump is the systolic pressure, while the position when
the thumping becomes inaudible is the diastolic pressure.
Some people experience high blood pressure related to anxiety and nervousness
caused by a visit to a doctor's office, called white-coat syndrome. Patients
who experience this can use mobile blood pressure monitors away from the
doctor's office to accurately measure their blood pressure.
TREATMENT APPROACH
Primary hypertension can be controlled, but not cured. Secondary hypertension
can be cured by treating the underlying condition. Because a person's diet and
exercise habits can affect blood pressure, physicians first recommend making
lifestyle changes, including:
- Stopping smoking;
- Losing weight;
- Limiting alcohol consumption to 1 to 2 drinks per day;
- Exercising; and
- Eating a low-sodium diet.
Physicians commonly prescribe medications in addition to recommending lifestyle
changes, or if lifestyle changes do not control hypertension. Medications called
antihypertensives are commonly prescribed to control hypertension including:
- Centrally acting agents (affect brain chemistry);
- Peripherally acting agents (act on the nerves that regulate blood pressure);
- Direct-acting vasodilators (relax blood vessel walls);
- Beta-blockers;
- Calcium channel blockers;
- Diuretics; and
- Angiotensin drugs.
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