High blood pressure (hypertension) is a major health problem in the United States. Untreated, high blood pressure will cause the heart to eventually overwork itself to the point at which serious damage can occur. For instance, the heart muscle can thicken (hypertrophy) and function abnormally, or dilate and contract less forcefully (dilated cardiomyopathy). High blood pressure can also cause injury to the brain, the eyes and the kidneys, where delicate arteries are damaged by the increased pressure.
High blood pressure is considered a major risk factor for heart attack, heart failure and stroke. About half of people having first-time heart attacks and two-thirds of people having first-time strokes suffer from high blood pressure. Most cases of high blood pressure have no cure, but the overwhelming majority can be managed and controlled with diet and medication.
High blood pressure affects one out of every three Americans or 65 million people, according to the American Heart Association (AHA). An additional 28 percent of Americans, or 59 million people, have prehypertension, which is defined as blood pressure that is on the borderline between normal and elevated. Of the people with high blood pressure, 28 percent do not know they have the condition. Among the 61 percent who are under treatment, only 35 percent have their blood pressure adequately controlled.
High blood pressure is not evenly distributed throughout the population. Until age 55, it is more common among men than women. However, after menopause (which occurs usually around age 50), women's blood pressure steadily risks, possibly because of the loss of hormones. By age 75, high blood pressure is more common among women than men.
High blood pressure also occurs disproportionately more often in minority communities. According to the AHA, the prevalence of high blood pressure among black Americans is the highest in the world. Black women, especially, are prone to high blood pressure. Statistically, they have an 85 percent higher rate of medical care visits for high blood pressure than white women. Similarly, people of Hispanic descent, as well as those of American Indian of Alaskan native ancestry, suffer from higher rates of high blood pressure.
High blood pressure rates are also rising among American children, alongside an epidemic of obesity. Researchers report that supplementing infant formula with polyunsaturated fatty acids appears to have a beneficial impact on blood pressure later on in childhood. Previous studies already showed that breast milk contains such fatty acids and that breast-fed children had lower blood pressures than those who were formula-fed.
About high blood pressure
High blood pressure (hypertension) is a condition in which a person’s blood pressure is elevated. Blood pressure is the measure of the force of the blood pushing against the walls of the arteries – the blood vessels that carry blood from the heart to the rest of the body. If the high blood pressure has no known cause (more than 90 percent of cases), it is known as primary, essential or idiopathic hypertension. If it is caused by another condition, such as kidney disease, it is known as secondary hypertension. However, because of the complex variety of systems that influences blood pressure, these distinctions have blurred somewhat in clinical practice.
Blood pressure measurement is inexpensive and easily performed. Blood pressure is measured in two phases that correspond to the natural contractions of the heart. When the heart contracts (e.g., systole), the pressure of blood against arterial walls is known as systolic pressure. When it relaxes (diastole), the pressure of blood against arterial walls is known as diastolic pressure.
Blood pressure is always expressed as systolic pressure over diastolic pressure. Normal blood pressure for adults is considered to be below 120/80 millimeters of mercury (mm/Hg). Generally, blood pressure above 140/90 is considered to be high for adults, and blood pressure under 90/60 is considered to be low for adults (hypotension). High blood pressure may be diagnosed if an individual has any of the following three conditions:
Has a blood pressure reading of 140/90
Is taking antihypertensive medication
Has been found twice by a physician to have high blood pressure
A new category, prehypertension, is being used to refer to individuals with blood pressures between 120-139/80-89. Such individuals are typically not prescribed medication, but they are advised to adopt lifestyle modifications to help keep blood pressure from rising. Lifestyle modifications might include weight loss, diet, exercise, reducing salt intake and quitting smoking.
Although the cause of most cases of high blood pressure is unknown, researchers have uncovered evidence that blood pressure is associated with insulin resistance and/or elevated insulin levels (hyperinsulinemia). Both high blood pressure and insulin resistance are features of the metabolic syndrome, a cluster of abnormalities that includes obesity, elevated triglycerides and low HDL "good" cholesterol. A number of possible mechanisms have been proposed that would explain how insulin resistance contributes to hypertension. However, this link is still poorly understood.
Researchers have also identified dozens of genes that contribute to high blood pressure. Though this implies that some people inherit a propensity for high blood pressure, the association is more complicated. Researchers believe that about 30 percent of essential hypertension can be traced back to genetic abnormalities that run in families. Most recent studies seem to indicate that inherited high blood pressure is the result of multiple gene expressions. There is currently no genetic test that consistently identifies people at risk for developing high blood pressure.
Whatever its cause, high blood pressure exacts a tremendous cost from society. High blood pressure is a major risk factor for heart attack, stroke and heart failure. According to the American Heart Association, about 69 percent of people who have a first heart attack, 77 percent who have a first stroke and 74 percent who have congestive heart failure have blood pressure higher than 140/90 mm Hg. High blood pressure has also been linked to sleep apnea, which itself is associated with heart disease. Some recent research suggests that premature birth in males may result in an increased risk of high blood pressure later in life.
Overall, an estimated 28 percent of American adults have high blood pressure. Of those, 30 percent do not know they have the dangerous condition, which is why it has been sometimes called the “silent killer.” Prehypertension is present in about 28 percent of American adults, or about 59 million people. Among the people who have been diagnosed, adequate blood pressure control is a significant problem. According to estimates from the National Institutes of Health, as many as 70 percent of people who are diagnosed with high blood pressure do not have it adequately controlled.
Before age 55, men are more likely to suffer from high blood pressure than women. After age 50, however, women experience a gradual rise in blood pressure, possibly due to the loss of hormones associated with menopause. By age 74, women are much more likely to have high blood pressure than men. It is two to three times more common in women taking birth control pills than those not taking them, especially in women who are overweight or obese.
The condition is especially deadly among black Americans, who tend to be diagnosed at younger ages and with higher blood pressures than other ethnic groups. Within the black community, high blood pressure is more likely to be diagnosed among people who are middle-aged or older, less educated, overweight or obese, physically inactive, and have diabetes. Black women, in particular, seem to suffer from high rates of elevated blood pressure. They have an 85 percent higher rate of medical care visits for high blood pressure than white women.
Despite its wide-ranging reach and potentially serious consequences, high blood pressure is relatively easy to diagnose and can be controlled, either with medications or lifestyle modifications. It is very important that people with high blood pressure seek treatment and follow their physician’s plan. Left untreated, high blood pressure will gradually continue to rise, causing the heart to overwork itself to the point at which serious damage can occur. Untreated high blood pressure also places other systems (e.g., circulation) and organs (e.g., the kidneys) at greater risk of damage that could lead to dysfunction or failure.
Aortic aneurysm (a weakness in the aortic wall where it balloons out to more than 1.5 times its normal size and is in danger of rupturing), often resulting in sudden cardiac death
Kidney failure
Retinopathy (eye disease that leads to loss of vision)
The risk of developing one or more of these serious health conditions increases as blood pressure rises. To help physicians and patients better understand the dangers associated with high blood pressure, blood pressure measurements have been ranked into categories based on increasing severity. The following categories apply to adults (age 18 and over) who are not taking medicine for high blood pressure and do not have a serious short-term illness:
Stage
Systolic Pressure
Diastolic Pressure
Optimal *
Under 120
AND
Under 80
Prehypertensive**
120-139
OR
80-89
1
140-159
OR
90-99
2
160-179
OR
100-109
3
180 or over
OR
110 or over
Source: National High Blood Pressure Education Program
* Optimal levels are with respect to heart disease risk. Unusually low readings (below 90/60) can also negatively affect heart health and should be reported to a physician.
**Prehypertension refers to individuals who do not have high blood pressure and who do not take blood pressure medication (antihypertensives) but who are considered to be at risk for developing high blood pressure and its associated risk for coronary artery disease and stroke. Earlier, such individuals may have been termed “high normal.” Prehypertensive individuals are typically not given medication, but are recommended to adopt lifestyle modifications where necessary to help keep blood pressure from rising. These include weight loss, diet, exercise, reducing salt intake, limiting alcohol intake and stopping smoking.
Although 120/80 is considered ideal, researchers at the National Heart, Lung and Blood Institute (NHLBI) report that the risk of developing coronary artery disease can begin at blood pressures little higher than 115/75 mmHg, and that risk doubles with each 20/10 mmHg increment.
An important exception to the information listed above is noted among patients with diabetes and/or kidney disease. In these patients, hypertension is associated with an exceptionally higher rate of complications. These patients will require treatment if their blood pressure is above 130/85. Research has found success with a new drug, indapamide. For individuals with diabetes and high blood pressure, the drug was seen to lower blood pressure without affecting blood sugar levels.
Signs and symptoms of high blood pressure
The majority of people with mild to moderate high blood pressure cannot tell when their blood pressure is too high. In fact, about one-third of hypertensive people are not aware of their condition. If symptoms are present, patients may experience chest pain (angina), shortness of breath or other symptoms related to heart disease or underlying damage. High blood pressure may cause any of the following:
Fatigue
Confusion
Nausea or upset stomach
Vision changes or problems
Excessive sweating
Paleness or redness of skin
Nosebleeds
Anxiety or nervousness
Strong, fast or obviously irregular heartbeat (palpitations)
Ringing or buzzing in ears
Erectile dysfunction (impotence)
Headache
Dizziness
Diagnosis methods for high blood pressure
The diagnosis for high blood pressure begins with the physician taking a patient’s full medical history. During the medical history, the physician will ask ask about heart-related problems in the family (e.g. high blood pressure, coronary heart disease). The physician will also question the patient about lifestyle habits, such as diet, exercise and stress.
After obtaining a thorough medical history, the physician will complete a physical examination, which will include checking the patient’s blood pressure in both arms while standing and lying down. In some cases, the physician may ask the patient to take his or her own blood pressure at home and provide a daily log of blood pressure measurements. This strategy will help establish the patient’s normal blood pressure pattern and rule out white coat hypertension (high blood pressure that is caused by anxiety from being in a physician’s office). It has also been shown that, in adults 65 years of age and older, blood pressure may drop somewhat in the first two hours after eating. This may result in an inaccurate blood pressure reading if taken during that interval. In addition, blood pressure readings may be affected if an individual drinks caffeine or smokes cigarettes 30 minutes before blood pressure is taken. Individuals also should go to the bathroom prior to the reading as a full bladder can change a blood pressure reading.
Typically, blood pressure is measured by wrapping an arm cuff (attached to a sphygmomanometer) snugly around the patient’s arm and then using a stethoscope to listen to the brachial artery located at the inside elbow on the same arm. The cuff is pumped full of air until circulation is very briefly cut off. Then some air will be slowly let out of the device, loosening the cuff’s grip on the arm and allowing the blood to flow freely again. As the air is let out, the examiner watches the numbers drop on a simple monitor (sphygmomanometer) and waits until a heartbeat is heard. The number at which that occurs is the systolic pressure. The examiner remembers this as the numbers continue to come down on the monitor and notes the number at which he or she last hears the heartbeat. The number at which that occurs is the diastolic pressure. Other blood pressure measurement devices may also be used. Some use mercury manometers to measure the pressure and others employ digital devices.
Reliable blood pressure monitors are available for people who are interested in monitoring their own blood pressure and/or that of their family members. When purchasing these monitors, it is important to consult with a physician or a consumer product-rating agency regarding the reliability of home monitors. Generally, arm cuff digital monitors are the easiest and most reliable to use but should be periodically checked with a mercury sphygmomanometer. Researchers are also testing 24-hour blood pressure monitors, with early studies focusing on patients with high blood pressure who are at increased risk for a heart attack.
According to the American Heart Association, automated blood pressure devices found in some public areas (e.g., drug stores) should generally not be considered reliable or accurate measuring devices. These machines are often poorly maintained and can return inaccurate results for large individuals.
Also, ambulatory blood pressure monitoring has revealed that in normal individuals, blood pressure is higher during the morning hours and drops at night (also called the dipping phenomenon). The absence of normal dipping is abnormal and has been associated with increased risk of cerebral and cardiac complications in patients with and without established hypertension.
Following the physical examination, a number of tests may be ordered, which include:
Urinalysis and various blood tests (e.g., electrolytes and waste products) tests to rule out kidney disease. Blood glucose testing and a complete lipid profile, including cholesterol and triglyceride levels, is also usually recommended. Other blood tests including thyroid function tests and white blood cell counts, plus calcium and phosphate levels.
Electrocardiogram (EKG), which measures the heart’s electrical activity. By analyzing the EKG results, a physician can check for heart-related problems that could be associated with high blood pressure (e.g., left ventricular hypertrophy), which can occur as a result of long-term, uncontrolled high blood pressure. Doppler studies can also detect abnormalities in heart relaxation (diastolic dysfunction), as a complication of hypertension.
Echocardiogram, which uses ultrasound waves to visualize the structures and functions of the heart. This test is also used to check for heart–related problems such as left ventricular hypertrophy.
Chest x-ray to rule out an enlarged heart.
Once a diagnosis has been made and serious problems (e.g., kidney disease) have been ruled out, treatment can begin. However, very high blood pressure may require additional testing to rule out an unusual cause. For example, a renal Doppler sonogram or scan may be ordered to evaluate for high blood pressure related to kidney disease or caused by renal artery stenosis (narrowing). Also, a 24-hour urine test may be needed to rule out an endocrine disorder, such as Cushing disease or pheochromocytoma.
High blood pressure may occur in either adults or children. Some people may also be diagnosed with the opposite condition, low blood pressure (hypotension). Although some people with high blood pressure do not need to take medication providing they can control their risk factors (e.g., weight), most people will generally require long-term treatment with medications.
Treatment options for high blood pressure
Depending on the severity of high blood pressure, the physician may recommend lifestyle modifications, either with or without medications. In general, patients with a blood pressure reading of 140/90 or greater are candidates for medical intervention, in addition to lifestyle changes. Patients with isolated systolic hypertension (e.g., a blood pressure reading of 160/89) over the age of 65 are also candidates for medical therapy. Prehypertensive patients are generally advised to make a number of lifestyle changes before medical therapy is begun. Definite steps that should be taken to lower and control blood pressure include:
Quitting smoking. This is perhaps the most important thing a smoker can do to promote his or her own health. Among many other side effects, smoking elevates blood pressure.
Losing weight. Loss of weight, especially in the abdominal area, can immediately reduce blood pressure and help reduce the size of the heart. Weight loss accompanied by salt restriction may allow mild hypertensives to reduce or eliminate their need for medication.
Following the DASH diet. Well-controlled studies have shown that people on the American Heart Association’s Dietary Approaches to Stop Hypertension diet, or “DASH” diet, for only eight weeks experienced a significant reduction in blood pressure. The DASH diet emphasizes fruits, vegetables, whole grains and low-fat dairy while limiting saturated fat and red meat.
Getting adequate amounts of vitamins and minerals. Studies show that vitamin C protects normal levels of nitric oxide – the substance that keeps arteries flexible. Vitamin E and the B-vitamins may also be helpful. Also, adequate intake of minerals such as potassium, magnesium and calcium is thought by some experts to be even more helpful than reducing salt intake for reducing blood pressure. Individuals should consult with their physician before supplementing their diet.
Engaging in regular aerobic exercise. Exercising three to four times per week is helpful for regulating high blood pressure, keeping in mind that the regularity of the exercise is more important than the intensity of the workout. For example, studies have shown that tai chi (an ancient Chinese workout involving slow, relaxing movements) may lower blood pressure almost as well as moderately intense aerobics. Individuals should consult with their physician before starting an exercise program.
Limiting alcohol use to one drink per day for women and two drinks per day for men. One drink is defined as one 6-ounce glass of wine per day, one 12-ounce beer or one 1-ounce shot of distilled spirits.
Limiting salt intake to 2,000 milligrams (2 grams) per day.
Using stress management techniques. Emotional factors may play important roles in the development of hypertension. Studies have shown that cognitive-behavioral therapy, transcendental meditation, active religious faith and participation in church-related activities are all associated with reducing blood pressure to healthy levels.
Having a pet may also lower blood pressure.
Women are encouraged to discuss with their physicians the increased risk of high blood pressure that results from taking birth control pills, particularly if they are over the age of 35. According to the American Heart Association, high blood pressure is two to three times more common in women taking birth control pills than those not taking them, especially in women who are overweight or obese. Also, studies have shown that women who develop high blood pressure during pregnancy have a higher risk of stroke, heart disease and kidney disease later in life.
As hypertensive patients make these changes, they are often encouraged to monitor their blood pressure at home, under the guidance of their physician. In addition to these lifestyle changes, patients are often prescribed blood pressure-reducing medications. These medications include:
Diuretics. Medications that promote the formation of urine in the kidneys, causing the body to flush out excess fluids and minerals, especially sodium. These are often the first medications given to reduce high blood pressure. Though commonly used, they may have unwanted side effects, such as low potassium levels (hypokalemia). This side effect can be minimized with the use of potassium-sparing diuretics.
Alpha blockers and beta blockers. Medications that inhibit alpha and beta receptors in various parts of the nervous system. This helps arteries to relax, decreases the force of the heartbeat and reduces blood pressure. Beta blockers are especially useful in patients with heart disease, but they should be used with caution among diabetic patients because they interfere with the body's normal responses to fluctuating glucose levels. Alpha blockers work by interfering with norepinephrine, which causes increased cardiac activity. They are not usually used as first-line therapy, however, because patients may develop a tolerance to the medication and their use has recently been implicated in an increase in cardiovascular events.
ACE inhibitors. These medications are vasodilators that help to reduce blood pressure by inhibiting substances in the blood that cause blood vessels to constrict. Recent studies suggest that this class of drugs may be superior to others in preventing stroke, heart disease and kidney disease in patients (especially diabetic individuals) with risk factors for vascular disease. They are also very useful in patients with established heart disease.
Angiotensin II receptor blockers (ARBs). This new class of drugs is showing good results and great promise in reducing complications related to high blood pressure. They have similar effects to ACE inhibitors, although they are more specific in their mode of action and have fewer side effects. Although beta blockers, ACE inhibitors and diuretics are currently used most often in the treatment of high blood pressure, ARBs may be prescribed more often in the future.
Calcium channel blockers. These are vasodilators that inhibit the flow of calcium into heart and blood vessel tissues, which reduces tension in the heart, relaxes blood vessels and lowers blood pressure. However, most studies have not shown that these agents reduce the risk of death from high blood pressure, and some of these medications may increase the risk of death from high blood pressure.
Though some of the newer medications have been shown to lower both blood pressure and the risks of heart disease, they had not been tested against each other until recently. This was addressed with the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). Begun in 1994, involving more than 42,000 individuals and the largest such trial to date, this important study showed that “traditional” diuretics were more effective in treating high blood pressure and should be used as first-line therapy. Participants with high blood pressure were randomly given diuretics, calcium channel blockers, ACE inhibitors or alpha blockers.
Results five years later revealed that, compared to the other classes of drugs in the study, diuretics were not only significantly more effective in lowering high blood pressure, but also in lowering the risk of cardiovascular events (e.g., stroke, angina, heart failure). In fact, the alpha blocker category was terminated in March 2000 due to a higher rate of cardiovascular events and hospitalization compared to diuretics. Based on these findings, the ALLHAT researchers concluded that drug therapy to lower blood pressure should be initiated with diuretics.
The ALLHAT researchers did recognize some limitations to the study. Commenting on the significantly lower blood pressure attained with the diuretic-controlled group (compared to calcium channel blockers and ACE inhibitors), the benefit may have been secondary to overall better blood pressure control in that group and perhaps not just from the diuretic itself. Indeed, other studies have shown a marked and significant benefit from ACE inhibitors, specifically ramipril, in reducing the progression of atherosclerosis, preventing strokes and heart attacks, and prolonging life in patients with vascular disease, high blood pressure, diabetes and heart failure.
Additional research has focused on risks associated with drugs used to treat hypertension. Recent studies have suggested that some blood pressure drugs may boost the risk of diabetes, especially among those who are already at risk for the disease. Beta blockers and diuretics are the classes of drugs most closely associated diabetes. In contrast, ARBs and ACE inhibitors were least related to the disease. Additional research is necessary to confirm the results of these studies.
Scientists are also examining the use of a drug combination for effective treatment of high blood pressure. Most patients take separate antihypertensive drugs to control their high blood pressure. Researchers are evaluating the combination of lower doses of established antihypertensives in a single capsule. Scientists believe considerable research is necessary to determine the benefits of this treatment approach.
The majority of patients with high blood pressure will need to take medications for the rest of their lives in order to control the condition. In some cases, two or three antihypertensives may be given. Recent studies have shown that such a combination of drugs not only lowers blood pressure but also may reduce the risk of stroke and ischemic heart disease. Other research has suggested that some patients with only slightly elevated blood pressures may eventually be able to stop taking medications and control their condition through lifestyle changes alone. The two most important lifestyle changes tracked by the study were weight loss and maintaining a low-salt diet. Strategies such as exercise, diet plans and, especially, changes in drugs should be discussed with a physician before they are attempted.
Researchers have also been exploring the genetic roots of high blood pressure. Identifying genes that cause high blood pressure in a particular patient could help physicians to prescribe the most effective antihypertensive drug.
Lifestyle considerations
People with high blood pressure should avoid certain activities and situations that may raise their heart rates and blood pressure to dangerous levels. These include:
Saunas or steam rooms
Steam baths
Heated whirlpools
Hot tubs
Very warm swimming pools
It is very important for hypertensive people to limit the amount of time spent in these activities to less than 10 minutes. After exposure to these environments, individuals should sit down out of the heat for a few minutes before standing to minimize the risk of dizziness or fainting (syncope).
Hypertensive individuals must also be careful about using certain over-the-counter (OTC) medications that contain vasoconstrictors, which can elevate blood pressure. Such medications include:
Eyedrops
Antihistamines
Cold, flu, sinus and cough medications (especially those containing decongestants)
Hypertensive patients are also encouraged to follow all of their physician’s orders regarding treatment in order to prevent serious health consequences. Patients are also encouraged to discuss with their physicians any side effects or other concerns that they may have about their treatment.
Women’s issues with high blood pressure
Once thought of as a male disease, high blood pressure affects an equal number of women and men, according to the American Heart Association. Until age 55, more men than women have high blood pressure. However, after menopause, which typically occurs around age 50, women begin to experience a rise in blood pressure. Researchers believe this may be due to the loss of sex hormones, including estrogen and progesterone, but the exact mechanism that causes this is unclear. By age 74, more women than men have high blood pressure. As with men, high blood pressure in women usually develops without symptoms, and, though treatable, generally has no cure. All women are encouraged to learn about their risks for high blood pressure and what can be done to prevent it.
Below are some facts about women and high blood pressure:
One in three cases of heart failure in women results from high blood pressure.
Blood pressure tends to get higher as women age. More than half of women over age 50 suffer from high blood pressure.
High blood pressure is two to three times more common in women taking birth control pills than those not taking them, especially among women who are overweight or obese.
Women who have had a heart attack are less likely to experience a second one if they lower their blood pressure.
High blood pressure is more prevalent among black women than in the general female population.
During pregnancy, some women develop high blood pressure for the first time. Known as gestational hypertension, this has been shown to increase the risk of developing high blood pressure and stroke later on in life. Others who already have the condition see it worsen during pregnancy. High blood pressure is also connected to a condition called preeclampsia, which is related to high blood pressure and protein in the mother’s urine. It is the second leading cause of maternal death in the United States.
Sexual dysfunction in women may be linked to high blood pressure. Female patients are encouraged to discuss any sexual difficulties with their physicians.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to high blood pressure:
What is my blood pressure?
Is my blood pressure considered too high or too low?
Am I at high risk for high blood pressure?
Should I have my blood pressure monitored for 24 or 48 hours?
What additional diagnostic tests might I need?
What could be the cause of my high blood pressure?
What are my risks for cardiovascular conditions from high blood pressure?
What lifestyle changes should I make to lower my blood pressure?
Will lifestyle changes be tried before you recommend medication?
What medications do you recommend for my high blood pressure?
What are the benefits and risks with these medications?
How quickly can I expect to see a drop in my blood pressure?
How long will I need to be on the medication?
How often should I have my blood pressure checked?
Should I get a home blood pressure device?
What blood pressure reading indicates a medical emergency?
Will my high blood pressure place my children at higher risk for the condition?
