Hypertension is elevated blood pressure that is consistently above normal ranges. Hypertension can go undetected for years while it causes irreparable organ damage, even leading to sudden death from a stroke or heart attack.
Blood pressure is a measure of the force of blood that is pushing against the inside of artery walls. The more blood the heart pumps and the more resistance in the arteries, the greater the blood pressure.
Blood pressure is measured in millimeters of mercury (mm Hg) as two numbers, written like a fraction. Normal blood pressure is considered below 120/80 mm Hg. Pressure that consistently equals or exceeds 140/90 mm Hg diastolic is considered high. Diastolic blood pressure that reaches 120 mm Hg requires urgent treatment to prevent heart failure or other complications.
People with systolic blood pressure between 120 and 139 or diastolic blood pressure between 80 and 89 are considered prehypertensive and should modify lifestyle factors such as diet and exercise to prevent cardiovascular disease.
Hypertension adversely affects the heart, the blood vessels, and other organs and can lead to the following health problems:
- Congestive heart failure;
- Atherosclerosis, or hardening of the arteries;
- Tissue death or failure of organs such as the kidneys;
- Stroke; and
- Aneurysms, or bulges in arteries that are subject to rupture.
WHAT ARE THE SYMPTOMS?
Hypertension has no symptoms. Symptoms only occur after complications develop and may include one or more of the following:
- Blurred vision;
- Headaches; and
- Facial flushing.
Symptoms of severe hypertension can advance to:
- Irregular or rapid heartbeat;
- A buzzing noise in the ear;
- Shortness of breath; and
- Blurred vision.
CAUSES AND RISK FACTORS
In 85 percent to 90 percent of cases there is no known cause for hypertension. This kind of hypertension is known as primary. There are a number of risk factors that may contribute to primary hypertension, including:
- Race, in that African Americans are more likely to develop hypertension than white Americans;
- Male gender (until the age of 55 and older, when women become more likely to develop hypertension);
- Being overweight; and
- Not exercising.
When high blood pressure occurs because of a medical condition or medication, it is referred to as secondary. Factors that may contribute to secondary hypertension include:
- Blockage of artery blood flow to the kidneys;
- Kidney disease;
- A tumor of the adrenal gland;
- A congenital defect of the aorta;
- A hormonal disorder;
- Hyperthyroidism; and
- Use of alcohol, oral contraceptives, or corticosteroids.
Blood pressure is measured using a sphygmomanometer-an inflatable arm cuff attached to a pressure gauge-and a stethoscope.
To measure blood pressure, the cuff is wrapped around the upper arm and the stethoscope is placed at or near the inside of the elbow. The cuff is inflated until the pressure gauge reading is at least 30 mm Hg higher than the expected systolic blood pressure.
As the cuff is slowly deflated, the pulse becomes audible and then stops briefly before returning. The pressure reading at which the pulse is first heard is the systolic pressure. The reading at which the pulse ceases to be audible is the diastolic pressure.
If hypertension is diagnosed, additional tests are commonly ordered to determine if organ damage has occurred because of the condition. These tests include:
- Electrocardiography (ECG);
- Urine analysis;
- Blood analysis;
- Chest x ray; and
- Eye examination.
Though incurable, hypertension can be treated successfully through lifelong lifestyle modifications and, when needed, medication.
For mild hypertension, positive lifestyle changes are usually enough to reduce blood pressure. Some lifestyle changes to consider are:
- Stop smoking;
- Lose weight;
- Moderate alcohol intake;
- Exercise regularly; and
- Eat a healthy diet.
If lifestyle changes do not reduce blood pressure sufficiently, or if high blood pressure is severe or complicated by medical conditions such as heart disease or diabetes, medications may be prescribed.
The most commonly prescribed antihypertensives are:
- ACE (angiotensin-converting enzyme) inhibitors;
- Angiotensin II receptor blockers; and
- Calcium channel blockers.