Introduction
You can't feel it. You can't see it. Nevertheless, your blood pressure may be high. If it is, you have hypertension, commonly called "the silent killer." You cannot afford to ignore it.
What is it?
In hypertension, also known as high blood pressure, blood is forced through the heart and vessels throughout the body with a greater force than is necessary. Over time, hypertension damages the heart and blood vessels. Eventually, untreated hypertension can lead to life-threatening health problems such as heart disease and strokes.
When your blood pressure is checked, two measurements--systolic and diastolic--are taken.
Systolic blood pressure represents the peak pumping pressure of your heart when it is fully contracted during a heartbeat.
Diastolic blood pressure represents the pressure in the heart when it is at rest between heartbeats. You may be diagnosed with hypertension if your systolic pressure is 140 or higher, and your diastolic is 90 or higher.
Normal blood pressure is defined as a systolic less than 120 and a diastolic less than 80 (or "less than 120 over 80"). "Pre-hypertension" is a new classification that impacts approximately 45 million American adults and is defined as a systolic of 120 to 139 and a diastolic of 80 to 89. Individuals who have pre-hypertension are on the brink of developing full blown hypertension.
Hypertension is defined as a systolic pressure of 140 or higher and/or a diastolic of 90 or higher. Hypertension is further classified by stages - stage 1 and stage 2 - depending on the systolic and diastolic pressure readings (see table below).
Hypertension is diagnosed when either the systolic or diastolic pressure is high or if both the systolic and diastolic pressures are high. To be diagnosed with hypertension, two or more properly measured blood pressure readings must be taken on each of two or more doctor's office visits and then the readings are averaged. This means it takes more than just one elevated blood pressure reading to be diagnosed with hypertension.
When the two blood pressure measurements fall into separate stages--for example a Stage 2 systolic reading, but a diastolic pressure in the normal range, the higher of the two is used for the classification. The higher part of the blood pressure measurement along with your personal risk for hypertension and other health conditions you may have, help your doctor determine the best treatment options for you. The table below lists the stages or classifications of hypertension.
| Systolic | Diastolic | |
| Normal | Less than 120 | Less than 80 |
| Pre-hypertension | 120 to 139 | 80 to 89 |
| Stage 1 | 140 to 159 | 90 to 99 |
| Stage 2 | 160 or higher | 100 or higher |
The higher the blood pressure, the more likely you are to experience a heart attack, stroke, heart failure or kidney disease.
What causes it?
Two main types of hypertension are recognized. By far the most common is Essential Hypertension, sometimes called Primary Hypertension. This is hypertension in which there is no identifiable cause. Ninety-five percent of all persons living with hypertension have essential hypertension. Although researchers have been unable to pinpoint its specific causes, several risk factors definitely increase an individual's chance of developing essential hypertension. Some of these risk factors are controllable. They include:
- Obesity
- High Salt Intake
- Smoking
- Lack of Exercise
- Emotional and/or Physical Stress
Risk factors that cannot be controlled are:
- Gender--Males are at a higher risk for hypertension at earlier ages than females.
- Age--The risk goes up for older women; more than half of women over the age of 60 have high blood pressure.
- Race--Hypertension and its complications are more common among people of African ancestry than among members of other ethnic groups. Not only does hypertension typically begin earlier among African-Americans; its complications are more frequent, and it leads to death more often.
- Family History of Hypertension--Risk is higher in people whose parents also have high blood pressure.
The other major type of hypertension, termed Secondary Hypertension, has an identifiable cause. It is due to disease. For example, kidney (renal) hypertension is due to high blood pressure within the arteries that supply blood to the kidneys. The underlying cause is kidney disease or conditions like atherosclerosis, which narrow or block the renal arteries. Secondary hypertension may also result from hormonal imbalances, particularly in the kidney's adrenal glands. Cushing's syndrome and pheochromocytoma (pronounced: "fee-oh-chrome-oh-sigh-toe-ma"), which is a tumor of the adrenal glands, are two of the conditions that can disrupt adrenal hormones and lead to secondary hypertension. Other causes of secondary hypertension include pregnancy, thyroid disease, and the use of some medications such as oral contraceptives and non-steroidal anti-inflammatory medications (NSAIDs).
Who has it?
According to estimates based on the Third National Health and Nutrition Examination Survey and on U.S. Census information, one-fourth of the general adult population in America has some degree of high blood pressure--a total of about 50 million people. Approximately 1 billion people worldwide have hypertension. Today it's estimated that there is a 19.3% prevalence of hypertension among white women, 24.4% among white men, 34.2% among black women, 35% among black men, 22% among Mexican-American women, and 25.2% among Mexican-American men.
Older persons also develop hypertension more often than younger individuals. Today it's estimated that in the older population (greater than 60 years of age), the prevalence of hypertension is 60%. As the population continues to age, it is expected that these numbers will also continue to increase. For unexplained reasons, people who live in the Southeastern part of the U.S. also seem to have higher rates of hypertension.
Approximately 45 million Americans have "prehypertension." These individuals are at increased risk for going on to develop hypertension.
What are the risk factors?
Risk factors are characteristics that may increase your chance for developing a condition. The more risk factors you have, the more likely you are to develop the condition. You are at increased risk for developing hypertension if you:
- Are 60 years of age or older
- Have a family history of hypertension
- Are of African-American descent
- Are overweight or obese
- Are a smoker
- Lack exercise or don't get enough physical activity
- Consume excessive amounts of alcohol (on a regular basis - defined as 3 or more drinks/day for a man or 2 or more drinks/day for a woman)
- Use oral contraceptives (birth control)
- Have a high salt intake and low potassium intake in your diet
Hypertension (high blood pressure) usually has no symptoms. That is why it is termed "the silent killer." However, it can be accompanied by the following, especially if blood pressure gets very high:
- Headache
- Confusion
- Numbness or tingling in the hands and feet
- Severe shortness of breath
The overall goal in treating hypertension is to prevent other health-related complications and death from hypertension-related complications. Treating and controlling your hypertension can help prevent damage to your heart, brain, kidneys, blood vessels, and eyes. For individuals who don't have other medical or health conditions such as diabetes or heart failure, typically the goal is to lower systolic blood pressure to less than 140 and the diastolic blood pressure to less than 90 ("less than 140 over 90"). For individuals with other medical conditions, blood pressure goals are lower and are determined by your doctor. For instance, the blood pressure goal for most people with diabetes is a systolic less than 130 and a diastolic less than 80 ("less than 130 over 80").
For individuals who have pre-hypertension, it is critical to adopt a healthy lifestyle to prevent high blood pressure. These lifestyle modifications include weight reduction, eating a healthy diet (called the "DASH" eating plan), increasing your amount of physical activity, and limiting alcoholic beverages. You can get more information about lifestyle modifications in the Helping Yourself section above.
For individuals with hypertension, lifestyle modifications as mentioned above are important but many times, medications will also be needed to adequately manage blood pressure. Many types of drugs are used to lower blood pressure. The initial drug choice is determined by your stage of hypertension (or how high your blood pressure is) and whether you have other health conditions that would affect the drug choice. (See the table below titled, "Options for Individualizing Antihypertensive Therapy" for more information.)
| Options for Individualizing Antihypertensive Drug Therapy | |
| If you have: | Then your doctor may prescribe one of the following: |
| Diabetes mellitus | ACE Inhibitors, ARBs, Diuretics, Beta Blockers, Calcium Channel Blockers |
| Diuretics, Beta Blockers, ACE Inhibitors, ARBs, spironolactone |
| Heart attack | Beta Blockers, ACE Inhibitors, spironolactone |
| Isolated systolic hypertension (elevated systolic only) | Diuretics, certain Long-acting Calcium Channel Blockers |
| Kidney Disease | ACE Inhibitors, ARBs |
| Recurrent Stroke Prevention | Diuretics, ACE Inhibitors |
For hypertension that isn't controlled by diet and exercise, new treatment guidelines for hypertension recommend that most patients be started on a thiazide-type diuretic, unless there is a compelling need for a different class of medications.
Thiazide diuretics are useful in achieving blood pressure control. They have been proven to enhance effectiveness of other antihypertensive medications when used in combination, and are typically more affordable than other antihypertensive medications.
Patients with Stage 1 hypertension are generally started on a thiazide-type diuretic, but ACE Inhibitors, angiotensin II receptor blockers (ARBs), beta blockers, calcium channel blockers, or combinations of different classes can also be considered. Patients diagnosed with Stage 2 hypertension typically need a combination of two drugs usually consisting of a thiazide diuretic along with an ACE Inhibitor, an ARB, a beta blocker or a calcium channel blocker to adequately lower their blood pressure. However, the treatment guidelines are meant only to be a guide. Your healthcare provider is in the best position to design a drug therapy regimen to manage your hypertension.
If the initial drug regimen does not achieve the goal blood pressure, your healthcare provider may change your regimen by increasing your dosage or by adding additional antihypertensive medications until your goal blood pressure is achieved. Many patients eventually require two or more drugs to effectively control their blood pressure. Some patients may even require four or five medications to control their blood pressure.
It is important to remember that everyone can respond to antihypertensive medications differently. What works for others may not work for you and vice versa. It is sometimes necessary for a doctor to prescribe different antihypertensive medications until the best regimen for you is found.
More severe hypertension may require the use of drugs called "vasodilators", which widen arteries, allowing blood to flow more easily and thus, lowering blood pressure. Oral vasodilators, such as hydralazine and minoxidil, are often used together with diuretics and other drugs that reduce fluid retention. Clonidine, another type of antihypertensive, may also be utilized.
Hypertension is typically a lifelong condition. However, some patients-- especially those who have made lifestyle modifications such as losing weight-- may be able to modify their antihypertensive medication regimen after hypertension has been controlled for at least one year. In so-called "Step-Down" therapy the number of drugs being used, their dosages, or both are gradually reduced to see if blood pressure remains controlled. The goal is to maintain blood pressure control using the lowest dosage of the least number of medications possible. The key though is to keep blood pressure at or under goal. Not all patients are able to "Step Down" from their antihypertensive therapy.Drug classes used to treat Hypertension (High Blood Pressure)
- ACE-Inhibitor and Calcium Channel Blocker Combination
- ACE-Inhibitor and Diuretic Combination
- ACE-Inhibitors
- Alpha Blockers
- Alpha-2 Agonists
- Angiotensin II Receptor Blocker and Diuretic Combinations
- Angiotensin II Receptor Blockers
- Beta Blockers
- Calcium Channel Blockers
- Combined Alpha and Beta Blockers
- Diuretics
- Renin Inhibitors
What is on the horizon?
Research is ongoing to better understand hypertension and how it develops. Researchers performed a study on newborns and found that healthy babies who had a "preferential response" to salt taste and who had at least one grandparent with a history of high blood pressure had blood pressures that averaged 5 millimeters of mercury (mmHg) or more higher than babies who had an aversive or neutral response to salt. Hypertension experts have long known that salt intake is linked to high blood pressure in some adults, especially those who are considered salt-sensitive, meaning that even low levels of salt trigger increases in blood pressure. While it is premature to suggest that neonatal testing can identify individuals at risk for adult hypertension, this research has spawned further investigation.
Researchers have also found that treating high blood pressure with medications not only lowers blood pressure but also makes the heart work better.
Researchers are also investigating a new class of drugs called vasopeptidase inhibitors. An investigational drug in this class called omapatrilat, was shown in one study to reduce blood pressure better than the well-known ACE inhibitors and appears to reverse some of the blood vessel stiffness thought to be an inevitable part of aging and a contributing factor to hypertension. Research continues on this drug class.
Researchers are also looking for a vaccine that would protect individuals against essential hypertension.
