High Blood Pressure Overview

The heart pumps blood into the arteries with enough force to push blood to the far reaches of each organ from the top of the head to the bottom of the feet. Blood pressure can be defined as the pressure of blood on the walls of the arteries as it circulates through the body. Blood pressure is highest as its leaves the heart through the aorta and gradually decreases as it enters smaller and smaller blood vessels (arteries, arterioles, and capillaries). Blood returns in the veins leading to the heart, aided by gravity and muscle contraction.

Hypertension is the medical term for high blood pressure. It is known as the "silent killer" since it has no initial symptoms but can lead to long-term disease and complications..

• Many people have high blood pressure and don't know it.
   

• Important complications of uncontrolled or poorly treated high blood pressure include heart attack, congestive heart failure, stroke, kidney failure, peripheral artery disease, and aortic aneurysms (weakening of the wall of the aorta, leading to widening or ballooning of the aorta).
   

• Public awareness of these dangers has increased. High blood pressure has become the second most common reason for medical office visits in the United States.

How is blood pressure measured?

Blood pressure is measured with a blood pressure cuff and recorded as two numbers, for example, 120/80 mm Hg (millimeters of mercury). Blood pressure measurements are usually taken at the upper arm over the brachial artery.

• The top, larger number is called the systolic pressure. This measures the pressure generated when the heart contracts (pumps). It reflects the pressure of the blood against arterial walls.
  
   

• The bottom, smaller number is called the diastolic pressure. This reflects the pressure in the arteries while the heart is filling and resting between heartbeats.

The American Heart Association has recommended guidelines to define normal and high blood pressure.

• Normal blood pressure less than 120/80
   

• Pre-hypertension 120-139/ 80-89
   

• High blood pressure (stage 1) 140-159/90-99
   

• High blood pressure (stage 2) higher than 160/100

As many as 60 million Americans have high blood pressure.

• Uncontrolled high blood pressure may be responsible for many cases of death and disability resulting from heart attack, stroke, and kidney failure.

High Blood Pressure Symptoms

High blood pressure usually causes no symptoms and high blood pressure often is labeled "the silent killer." People who have high blood pressure typically don't know it until their blood pressure is measured.

Sometimes people with markedly elevated blood pressure may develop:
* headache,
* dizziness,
* blurred vision,
* nausea and vomiting, and
* chest pain and shortness of breath.

People often do not seek medical care until they have symptoms arising from the organ damage caused by chronic (ongoing, long-term) high blood pressure. The following types of organ damage are commonly seen in chronic high blood pressure:

* Heart attack
* Heart failure
* Stroke or transient ischemic attack (TIA)
* Kidney failure
* Eye damage with progressive vision loss
* Peripheral arterial disease causing leg pain with walking (claudication)
* Outpouchings of the aorta, called aneurysms

About 1% of people with high blood pressure do not seek medical care until the high blood pressure is very severe, a condition known as malignant hypertension.

* In malignant hypertension, the diastolic blood pressure (the lower number) often exceeds 140 mm Hg.
* Malignant hypertension may be associated with headache, lightheadedness, nausea, vomiting, and stroke like symptoms
* Malignant hypertension requires emergency intervention and lowering of blood pressure to prevent brain hemorrhage or stroke.

It is of utmost importance to realize that high blood pressure can be unrecognized for years, causing no symptoms but causing progressive damage to the heart, other organs, and blood vessels.