High Blood Pressure

Blood pressure is determined by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries.  The more blood your heart pumps and the narrower your arteries, the higher your blood pressure.  High blood pressure (HBP), also called hypertension, can exist for years without a single symptom, and, if untreated, can damage arteries and vital organs throughout the body.  That’s why high blood pressure is often called the “silent killer.”

High Blood Pressure Facts

  • About one in three (33.6%) U.S. adults has high blood pressure.
  • High blood pressure is two to three times more common in women taking oral contraceptives, especially in obese and older women, than in women not taking them.
  • The prevalence of high blood pressure in African Americans in the United States is among the highest in the world, and it is increasing.  From 1988–94 and from  1999–2002, the prevalence of high blood pressure increased from 35.8 percent to 41.4 percent, and it was particularly high among African American women (44.0 percent).
  • Prevalence among whites also increased, from 24.3 percent to 28.1 percent.
  • About 69 percent of people who have a first heart attack, 77 percent who have a first stroke, and 74 percent with congestive heart failure have blood pressure higher than 140/90 mm Hg.

Blood Pressure Testing

Blood pressure testing is simple, quick and painless.  The most accurate reading of blood pressure is done using a blood pressure monitor, also known as a sphygmomanometer.

A blood pressure reading, given in millimeters of mercury (mm Hg), is recorded as two numbers written as a ratio, systolic and diastolic.  Systolic, which is the top and also the higher of the two numbers, measures the pressure in the arteries when the heart beats (when the heart muscle contracts).  Diastolic is the bottom and lower of the two numbers, and measures the pressure in the arteries between heartbeats (when the heart muscle is resting between beats and refilling with blood).  For people over 50, the top number (the systolic blood pressure) is more significant, as it is a major risk factor for cardiovascular disease.   In most people, systolic blood pressure rises steadily with age due to increasing stiffness of large arteries, long-term build-up of plaque, and increased incidence of cardiac and vascular disease.

While BP can change from minute to minute with changes in posture, exercise, stress or sleep, it should normally be less than 120/80 mm Hg (less than 120 systolic AND less than 80 diastolic) for an adult age 20 or over.  A single high reading above normal does not necessarily mean that you have high blood pressure.  However, if readings stay at 140/90 mm Hg or above (systolic 140 or above OR diastolic 90 or above) over time, your doctor will likely want you to begin a treatment program.

This chart reflects blood pressure categories defined by the American Heart Association.

Blood Pressure
Category
Systolic
mm Hg (upper #)
  Diastolic
mm Hg (lower #)
Normal
 
less than 120 and less than 80
Prehypertension 120139 or 8089
High Blood Pressure
(Hypertension) Stage 1
140159 or 9099
High Blood Pressure
(Hypertension) Stage 2
160 or higher or 100 or higher
Hypertensive Crisis
(Emergency care needed)
Higher than 180 or Higher than 110

 

Types and Causes of High Blood Pressure

  1. Primary (essential) Hypertension represents the majority – 90 to 95 percent – of high blood pressure cases in adults.  There is no identifiable cause and tends to develop gradually over many years.
  2. Secondary hypertension represents 5 to 10 percent of high blood pressure cases in adults.  It is caused by an underlying condition and tends to appear suddenly and cause higher blood pressure than does primary hypertension. Various conditions and medications can lead to secondary hypertension, including:
  • Kidney abnormalities
  • Tumors of the adrenal gland
  • Certain congenital heart defects
  • Certain medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs
  • Illegal drugs, such as cocaine and amphetamines

Symptoms of High Blood Pressure

Most people with high blood pressure have no signs or symptoms, even if blood pressure readings reach dangerously high levels.

Although a few people with early-stage high blood pressure may have dull headaches, dizzy spells or a few more nosebleeds than normal, these signs and symptoms typically don’t occur until high blood pressure has reached an advanced – even life-threatening – stage.

Risk Factors for High Blood Pressure

There are several factors that can increase the risk of developing high blood pressure, which can also increase the risk for heart attack, heart disease and stroke.

High blood pressure risk factors that can’t be changed:

  • Family history
  • Advanced age
  • Gender-related risk patterns:  A higher percentage of men than women have high blood pressure until 45 years of age.  From ages 45 to 54 and 55 to 64, the percentages of men and women with high blood pressure are similar.  After that, a much higher percentage of women have high blood pressure than men.

High blood pressure risk factors that can be changed:

  • Lack of physical activity
  • Poor diet, especially one that includes too much salt
  • Overweight and obesity
  • Excessive alcohol
  • Stress
  • Smoking and secondhand smoke

Complications of High Blood Pressure

High blood pressure creates excessive pressure on artery walls, which can damage blood vessels and organs.  The higher the blood pressure and the longer it goes uncontrolled, the greater the damage.  Uncontrolled high blood pressure can lead to:

  • Damage to your arteries
  • Aneurysm
  • Heart failure
  • Blocked or ruptured blood vessel in your brain – resulting in stroke
  • Weakened and narrowed blood vessels in your kidneys
  • Thickened, narrowed or torn blood vessels in the eyes,  resulting in vision loss
  • Metabolic syndrome,  disorders of your body’s metabolism,  creating a greater risk of developing diabetes, heart disease or stroke
  • Trouble with memory or understanding

Prevention

Tips on controlling blood pressure include:

  • Eat a healthy diet, which may require reducing salt
  • Exercise regularly
  • Maintain a healthy weight
  • Reduce and manage stress
  • Stop smoking
  • Comply with prescribe medications
  • Limit alcohol

Sources:

1American Heart Association, www.heart.org

2Heart Disease, Mayoclinic.com

3Heart Disease and Stroke Statistics, 2010 Update At-A-Glance, American Heart Association, www.heart.org

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