High Blood Pressure / Hypertension
What is high blood pressure?
High blood pressure or hypertension means high pressure (tension) in the arteries. The arteries are the vessels that carry blood from the pumping heart to all of the tissues and organs of the body. High blood pressure does not mean excessive emotional tension, although emotional tension and stress can temporarily increase the blood pressure. Normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called “pre-hypertension”, and a blood pressure of 140/90 or above is considered high blood pressure. The systolic blood pressure, which is the top number, represents the pressure in the arteries as the heart contracts and pumps blood into the arteries. The diastolic pressure, which is the bottom number, represents the pressure in the arteries as the heart relaxes after the contraction. The diastolic pressure, therefore, reflects the minimum pressure to which the arteries are exposed.
An elevation of the systolic and/or diastolic blood pressure increases the risk of developing heart (cardiac) disease, kidney (renal) disease, hardening of the arteries (atherosclerosis or arteriosclerosis), eye damage, and stroke (brain damage). These complications of hypertension are often referred to as end-organ damage because damage to these organs is the end result of chronic (long duration) high blood pressure. Accordingly, the diagnosis of high blood pressure in an individual is important so that efforts can be made to normalize the blood pressure and, thereby, prevent the complications. Since hypertension affects approximately 1 in 4 adults in the United States, it is clearly a major public health problem.
Whereas it was previously thought that diastolic blood pressure elevations were a more important risk factor than systolic elevations, it is now known that for individuals older than 50 years of age systolic hypertension represents a greater risk.
How is the blood pressure measured?
The blood pressure usually is measured with a small, portable instrument called a blood pressure cuff (sphygmomanometer). (Sphygmo in Greek means pulse, and a manometer measures pressure.) The blood pressure cuff consists of an air pump, a pressure gauge, and a rubber cuff. The instrument measures the blood pressure in units called millimeters of mercury (mm Hg).
The cuff is placed around the upper arm and inflated with the air pump to a pressure that blocks the flow of blood in the main artery (brachial artery) that travels through the arm. With the arm extended at the side of the body at the level of the heart, the pressure of the cuff on the arm and artery is gradually released. As the pressure in the cuff decreases, the health practitioner listens with a stethoscope over the artery at the front of the elbow. The pressure at which the practitioner first hears a pulsation over the artery is the systolic pressure. As the cuff pressure decreases further, the pressure at which the pulsation finally stops is the diastolic pressure.
How is high blood pressure defined?
Since blood pressure can be affected by several factors, it is important to standardize the environment with this in mind when blood pressure is determined. For at least one hour before measuring the BP one should avoid eating, strenuous exercise (which can lower blood pressure), smoking, and caffeine intake. Other stresses may alter the blood pressure and need to be considered when blood pressure is measured.
Even though most insurance companies, quite reasonably, consider high blood pressure to be 140/90 and higher for the general population, these levels may not be appropriate cut-offs for all individuals. As a matter of fact, many experts in the field of hypertension view blood pressure levels as a continuum, or range, from lower levels to higher levels. Such a continuum implies that there are no clear or precise cut-off values to separate normal blood pressure from high blood pressure. Individuals with so-called pre-hypertension (defined as a blood pressure between 120/80 and 139/89) may benefit from lowering of blood pressure by life style modification and possibly medication especially if there are other risk factors for end-organ damage such as diabetes or kidney disease (appropriate life style changes are discussed below).
For some people, blood pressure readings that are lower than 140/90 may be a more appropriate normal cut-off level. For example, in certain situations, such as in patients with long duration (chronic) kidney diseases that spill (lose) protein into the urine (proteinuria), the blood pressure is ideally kept at 130/80, or even lower. The purpose of reducing the blood pressure to this level in these patients is to slow the progression of kidney damage. Patients with diabetes (diabetes mellitus) may likewise benefit from blood pressure that is maintained at a level lower than 130/80. In addition, African Americans, who have an increased risk for developing the complications of hypertension, may decrease this risk by reducing their systolic blood pressure to less than 135 and the diastolic blood pressure to 80 mm Hg or less.
In line with the thinking that the risk of end-organ damage from high blood pressure represents a continuum, statistical analysis reveals that beginning at a blood pressure of 115/75 the risk of cardiovascular disease doubles with each increase in blood pressure of 20/10. This type of analysis has led to an ongoing “rethinking” in regard to who should be treated for hypertension, and what the goals of treatment should be.
Isolated systolic high blood pressure
Remember that the systolic blood pressure is the top number in the blood pressure reading and represents the pressure in the arteries as the heart contracts and pumps blood into the arteries. A systolic blood pressure that is persistently higher than 140 mm Hg is usually considered elevated, especially when associated with an elevated diastolic pressure (over 90). Isolated systolic hypertension, however, is defined as a systolic pressure that is above 140 mm Hg with a diastolic pressure that still is below 90. This disorder primarily affects older people and is characterized by an increased (wide) pulse pressure. The pulse pressure is defined as the difference between the systolic and diastolic blood pressures. An elevation of the systolic pressure without an elevation of the diastolic pressure, as occurs in isolated systolic hypertension, therefore, increases the pulse pressure. Stiffening of the arteries contributes to this widening of the pulse pressure.
Once considered to be harmless, an elevation of the pulse pressure is now thought to lead to health problems. In other words, a high pulse pressure is considered an important precursor or indicator of potential end-organ damage. Thus, isolated systolic hypertension is associated with a 2 to 4 times increased future risk of an enlarged heart, a heart attack (myocardial infarction), a stroke (brain damage), and death from heart disease or a stroke. Clinical studies in patients with isolated systolic hypertension have indicated that a reduction in systolic blood pressure by at least 20 mm to a level below 160 mm Hg reduces these increased risks.
White coat high blood pressure
A single elevated blood pressure reading in the doctor’s office can be misleading because the elevation may be only temporary. Presumably, such an elevation is caused by the patient’s anxiety that is related to the stress of the examination and fear that something will be wrong with their health. The initial visit to the physician’s office is often the cause of a spuriously high blood pressure that may disappear with repeated testing after rest and with followup visits and blood pressure checks. In fact, the suggestion has been made that about one out of four people that are thought to have mild hypertension actually may have normal blood pressure when they are outside of the physician’s office. This sort of elevated blood pressure, that is, an increase noted only in the doctor’s office, is called white coat hypertension. The name, of course, suggests that the white coat, which is symbolic for the physician, induces the patient’s anxiety and a transient increase in blood pressure. A diagnosis of white coat hypertension might imply that it is not a clinically important or dangerous finding.
However, caution is warranted in assessing white coat hypertension. An elevated blood pressure that is induced by the stress and anxiety of a visit to the doctor may not necessarily always be a harmless finding since other stresses in the patient’s life may likewise cause elevations in the blood pressure that are not ordinarily being measured. Accordingly, monitoring the blood pressure at home by blood pressure cuff or continuous monitoring equipment or at a pharmacy can help estimate the frequency and consistency of higher blood pressure readings. Additionally, conducting appropriate tests to search for any complications of hypertension can help evaluate the significance of variable blood pressure readings.
Borderline high blood pressure
Borderline hypertension is defined as mildly elevated blood pressure that is found to be higher than 140/90 mm Hg at some times and lower than that at other times. As in the case of white coat hypertension, patients with borderline hypertension need to have their blood pressure taken on several different occasions and their end-organ damage assessed in order to establish whether their hypertension is significant.
Keep in mind that people with borderline hypertension may have a tendency, as they get older, to develop more sustained or higher elevations of blood pressure. Accordingly, they have a modestly increased risk of developing heart-related (cardiovascular) disease. Therefore, even if the hypertension does not appear to be significant initially, people with borderline hypertension should have continuing follow-up of their blood pressure and monitoring for the complications of hypertension.
If, during the follow-up of a patient with borderline hypertension, the blood pressure becomes persistently higher than 140/ 90 mm Hg, an anti-hypertensive medication is usually started. Even if the diastolic pressure remains at a borderline level (usually under 90 mm Hg, yet persistently above 85) treatment may be started in certain circumstances.
What causes high blood pressure?
Two forms of high blood pressure have been described–essential (or primary) hypertension and secondary hypertension. Essential hypertension is a far more common condition and accounts for 95% of hypertension. The cause of essential hypertension is multifactorial, that is, there are several factors whose combined effects produce hypertension. In secondary hypertension, which accounts for 5% of hypertension, the high blood pressure is secondary to (caused by) a specific abnormality in one of the organs or systems of the body. (Secondary hypertension is discussed further in a separate section below.)
Essential hypertension affects approximately 75 million Americans, yet its basic causes or underlying defects are not always known. Nevertheless, certain associations have been recognized in people with essential hypertension. For example, essential hypertension develops only in groups or societies that have a fairly high intake of salt, exceeding 5.8 grams daily. In fact, salt intake may be a particularly important factor in relation to essential hypertension in several situations. Thus, excess salt may be involved in the hypertension that is associated with advancing age, African American background, obesity, hereditary (genetic) susceptibility, and kidney failure (renal insufficiency).
Genetic factors are thought to play a prominent role in the development of essential hypertension. However, the genes for hypertension have not yet been identified. (Genes are tiny portions of chromosomes that produce the proteins that determine the characteristics of individuals.) The current research in this area is focused on the genetic factors that affect the renin-angiotensin-aldosterone system. This system helps to regulate blood pressure by controlling salt balance and the tone (state of elasticity) of the arteries.
Approximately 30 % of cases of essential hypertension are attributable to genetic factors. For example, in the United States, the incidence of high blood pressure is greater among African Americans than among Caucasians or Asians. Also, in individuals who have one or two parents with hypertension, high blood pressure is twice as common as in the general population. Rarely, certain unusual genetic disorders affecting the hormones of the adrenal glands may lead to hypertension. (These identified genetic disorders are actually considered secondary hypertension.)
The vast majority of patients with essential hypertension have in common a particular abnormality of the arteries. That is, they have an increased resistance (stiffness or lack of elasticity) in the tiny arteries that are most distant from the heart (peripheral arteries or arterioles). The arterioles supply oxygen-containing blood and nutrients to all of the tissues of the body. The arterioles are connected by capillaries in the tissues to the venous system (or the veins), which returns the blood to the heart and lungs. Just what makes the peripheral arteries become stiff is not known. Yet, this increased peripheral arteriolar stiffness is present in those individuals whose essential hypertension is associated with genetic factors, obesity, lack of exercise, overuse of salt, and aging. Inflammation also may play a role in hypertension since a predictor of the development of hypertension is the presence of an elevated C reactive protein level (a blood test marker of inflammation) in some individuals.
What are the causes of secondary high blood pressure?
As mentioned previously, 5% of people with hypertension have what is called secondary hypertension. This means that the hypertension in these individuals is secondary to (caused by) a specific disorder of a particular organ or blood vessel, such as the kidney, adrenal gland, or aortic artery.
Renal (kidney) hypertension
Diseases of the kidneys can cause secondary hypertension. This type of secondary hypertension is called renal hypertension because it is caused by a problem in the kidneys. One important cause of renal hypertension is narrowing (stenosis) of the artery that supplies blood to the kidneys (renal artery). In younger individuals, usually women, the narrowing is caused by a thickening of the muscular wall of the arteries going to the kidney (fibromuscular hyperplasia). In older individuals, the narrowing generally is due to hard, fat-containing (atherosclerotic) plaques that are blocking the renal artery.
How does narrowing of the renal artery cause hypertension? First, the narrowed renal artery impairs the circulation of blood to the affected kidney. This deprivation of blood then stimulates the kidney to produce the hormones, renin and angiotensin. These hormones, along with aldosterone from the adrenal gland, cause a constriction and increased stiffness (resistance) in the peripheral arteries throughout the body, which finally, as mentioned previously, results in high blood pressure.
Renal hypertension is usually first suspected when high blood pressure is found in a young individual or a new onset of high blood pressure is discovered in an older person. Screening for renal artery narrowing then may include renal isotope (radioactive) imaging, ultrasonographic (sound wave) imaging, or magnetic resonance imaging (MRI) of the renal arteries. The purpose of these tests is to try to determine whether there is a restricted blood flow to the kidney and whether angioplasty (removal of the restriction in the renal arteries) is likely to be beneficial. However, if the ultrasonic assessment indicates a high resistive index within the kidney (high resistance to blood flow), angioplasty may not improve the blood pressure because chronic damage in the kidney from long-standing hypertension already exists. If any of these tests are abnormal or the doctor’s suspicion of renal artery narrowing is high enough, renal angiography (an x-ray study in which dye is injected into the renal artery) is done. Angiography is the ultimate test to actually visualize the narrowed renal artery.
A narrowing of the renal artery may be treated by balloon angioplasty. In this procedure, the physician threads a long narrow tube (catheter) into the renal artery. Once the catheter is there, the renal artery is widened by inflating a balloon at the end of the catheter and placing a permanent stent (a device that stretches the narrowing) in the artery at the site of the narrowing. This procedure usually results in an improved blood flow to the kidneys and lower blood pressure. Moreover, the procedure also preserves the function of the kidney that was partially deprived of its normal blood supply. Only rarely is surgery needed these days to open up the narrowing of the renal artery.
Any of the other types of chronic kidney disease that reduces the function of the kidneys can also cause hypertension due to hormonal disturbances and/or retention of salt.
It is important to remember that not only can kidney disease cause hypertension, but hypertension can also cause kidney disease. Therefore, all patients with high blood pressure should be evaluated for the presence of kidney disease so that they can be treated appropriately.
Adrenal gland tumors
Two rare types of tumors of the adrenal glands are less common, secondary causes of hypertension. (The adrenal glands sit right on top of the kidneys.) Both of these tumors produce excessive amounts of hormones (adrenal hormones) that cause high blood pressure. These tumors can be diagnosed from blood tests, urine tests, and imaging studies of the adrenal glands. Furthermore, surgery is often required to remove these tumors or the adrenal gland (adrenalectomy), which usually relieves the hypertension.
One of the types of adrenal tumors causes a condition that is called primary hyperaldosteronism because the tumor produces excessive amounts of the hormone aldosterone. In addition to the hypertension, this condition causes the loss of excessive amounts of potassium from the body into the urine, which results in a low level of potassium in the blood. Accordingly, hyperaldosteronism is generally first suspected in a person with hypertension when low potassium is also found in the blood. (Also, as previously mentioned, certain rare genetic disorders affecting the hormones of the adrenal gland can cause secondary hypertension.)
The other type of adrenal tumor that can cause secondary hypertension is called a pheochromocytoma. This tumor produces excessive catecholamines, which include several adrenalin-related hormones. The diagnosis of a pheochromocytoma is suspected in individuals who have sudden and recurrent episodes of hypertension that are associated with flushing of the skin, rapid heart beating (palpitations), and sweating, in addition to the symptoms associated with high blood pressure.
Coarctation of the aorta
Coarctation of the aorta is a rare hereditary disorder that is one of the most common causes of hypertension in children. This condition is characterized by a narrowing of a segment of the aorta, the main large artery coming from the heart. The aorta delivers blood to the arteries that supply all of the body’s organs, including the kidneys.
The narrowed segment (coarctation) of the aorta generally occurs above the renal arteries, which causes a reduced blood flow to the kidneys. This lack of blood to the kidneys prompts the renin-angiotensin-aldosterone hormonal system to elevate the blood pressure. Treatment of the coarctation is usually the surgical correction of the narrowed segment of the aorta. Sometimes, balloon angioplasty (as described above for renal artery stenosis) can be used to widen (dilate) the coarctation of the aorta.
The metabolic syndrome and obesity
Genetic factors play a role in the constellation of findings that make up the “metabolic syndrome.” Individuals with the metabolic syndrome have insulin resistance and a tendency to have type 2 diabetes mellitus (non-insulin-dependent diabetes). Obesity, especially associated with a marked increase in abdominal girth, leads to hyperglycemia (high blood sugar), elevated blood lipids (fats), vascular inflammation, endothelial dysfunction (abnormal reactivity of the blood vessels), and hypertension—all leading to premature atherosclerotic vascular disease. The epidemic of obesity in the United States contributes to this disorder in children, adolescents, and adults.
What do patients feel with high blood pressure?
Uncomplicated high blood pressure usually occurs without any symptoms. Therefore, hypertension has been labeled “the silent killer.” In other words, the disease can progress without symptoms (silently) to finally develop any one or more of the several potentially fatal complications of hypertension such as heart attacks or strokes. As a matter of fact, uncomplicated hypertension may be present and remain unnoticed for many years, or even decades. This happens when there are no symptoms, and those affected fail to undergo periodic blood pressure screening.
Some people with uncomplicated hypertension, however, may experience symptoms such as headache, dizziness, shortness of breath, and blurred vision. The presence of symptoms can be a good thing in that they can prompt people to consult a doctor for treatment and make them more compliant in taking their medications. Not infrequently, however, a person’s first contact with a physician may be after significant damage to the end-organs has occurred. In many cases, a person visits or is brought to the doctor or an emergency room with a heart attack, stroke, kidney failure, or impaired vision (due to damage to the back part of the retina). Greater public awareness and frequent blood pressure screening may help to identify patients with undiagnosed high blood pressure before significant complications have developed.
About one out of every 100 (1%) people with hypertension is diagnosed with severe high blood pressure (accelerated or malignant hypertension) at their first visit to the doctor. In these patients, the diastolic blood pressure (the minimum pressure) exceeds 140 mm Hg! Affected persons often experience severe headache, nausea, visual symptoms, dizziness, and sometimes kidney failure. Malignant hypertension is a medical emergency and requires urgent treatment to prevent a stroke (brain damage).
Which lifestyle modifications are beneficial in treating high blood pressure?
Lifestyle modifications refer to certain specific recommendations for changes in habits, diet and exercise. These modifications can lower the blood pressure as well as improve a patient’s response to blood pressure medications.
Alcohol
People who drink alcohol excessively (over two drinks per day) have a one and a half to two times increase in the prevalence of hypertension. The association between alcohol and high blood pressure is particularly noticeable when the alcohol intake exceeds 5 drinks per day. Moreover, the connection is a dose-related phenomenon. In other words, the more alcohol that is consumed, the stronger is the link with hypertension.
Smoking
Although smoking increases the risk of vascular complications (for example, heart disease and stroke) in people who already have hypertension, it is not associated with an increase in the development of hypertension. Nevertheless, smoking a cigarette can repeatedly produce an immediate, temporary rise in the blood pressure of 5 to10 mm Hg. Steady smokers however, actually may have a lower blood pressure than nonsmokers. The reason for this is that the nicotine in the cigarettes causes a decrease in appetite, which leads to weight loss. This, in turn, lowers the blood pressure.
Coffee
In one study, the caffeine consumed in 5 cups of coffee daily caused a mild increase in blood pressure in elderly people who already had hypertension, but not in those who had normal blood pressures. What’s more, the combination of smoking and drinking coffee in persons with high blood pressure may increase the blood pressure more than coffee alone. Limiting caffeine intake and cigarette smoking in hypertensive individuals, therefore, may be of some benefit in controlling their high blood pressure.
Salt
The American Heart Association recommends that the consumption of dietary salt be less than 6 grams of salt per day in the general population and a lower level (for example, less than 4 grams) for people with hypertension. To achieve a diet containing less than 4 grams of salt, a person should not add salt to their food or cooking. Also, the amount of natural salt in the diet can be reasonably estimated from the labeling information provided with most purchased foods.
Obesity
Obesity is common among hypertensive patients, and its prevalence increases with age. In fact, obesity may be what determines the increased incidence of high blood pressure with age. Obesity can contribute to hypertension in several possible ways. For one thing, obesity leads to a greater output of blood because the heart has to pump out more blood to supply the excess tissue. The increased cardiac output then can raise the blood pressure. For another thing, obese hypertensive individuals have a greater stiffness (resistance) in their peripheral arteries throughout the body. In addition, insulin resistance and the metabolic syndrome described previously occur more frequently in the obese. Finally, obesity may be associated with a tendency for the kidneys to retain salt. Weight loss may help reverse problems related to obesity while also lowering the blood pressure. It has been estimated that the blood pressure can be decreased 0.32 mm Hg for every 1 kg (2.2 pounds) of weight lost down to ideal body weight for the individual.
Some obese people, especially if they are very obese, have a syndrome called sleep apnea. This syndrome is characterized by the periodic interruption of normal breathing during sleep. Sleep apnea may contribute to the development of hypertension in this subgroup of obese individuals. This happens because the repeated episodes of apnea cause a lack of oxygen (hypoxia). The hypoxia then causes the adrenal gland to release adrenalin and related substances. Finally, the adrenalin and related substances cause a rise in the blood pressure.Exercise
A regular exercise program may help lower blood pressure over the long term. For example, activities such as jogging, bicycle riding, or swimming for 30 to 45 minutes daily may ultimately lower blood pressure by as much as 5 to15 mm Hg. Moreover, there appears to be a relationship between the amount of exercise and the degree to which the blood pressure is lowered. Thus, the more you exercise (up to a point), the more you lower the blood pressure. The beneficial response of the blood pressure to exercise occurs only with aerobic (vigorous and sustained) exercise programs. Therefore, any exercise program must be recommended or approved by an individual’s physician.
How is high blood pressure usually treated?
It is very important to take steps to control high blood pressure. If it is left untreated, it can result in heart disease or even stroke.
The good news is that high blood pressure can be well controlled by combining a healthy lifestyle with the correct medical treatment.
This can include synthetic prescription medication, natural remedies or a combination of both. If you are already taking prescription blood pressure medication, it is important to consult your doctor before making any changes.
There are a variety of prescription drugs available for high blood pressure including vasodilators, alpha-blockers, beta-blockers, diuretics, etc. Each has a unique way of working and different drugs may work for better different people.
You may need to try a variety before you find the right drug or combination of drugs suitable for you.
Like many synthetic drugs, anti-hypertensive medication has a risk of causing side effects depending on the person as well as the type of drug being taken.
These can include, dizziness, nausea, stomach problems, fatigue, impotence, insomnia, loss of appetite and others. Always speak to your doctor if you are experiencing any of these symptoms.
What about natural remedies?
There are many well known natural remedies for high blood pressure or hypertension.
Conventional medicines usually treat the symptoms of high blood pressure, but seldom address the underlying causes.
Naturopaths recognize that high blood pressure may be a sign or symptom of imbalance in the body. They believe in removing the causes of high blood pressure with a combination of lifestyle changes and natural remedies, rather than simply treating the symptoms.
Can herbal remedies and dietary supplements really help?
There is a great deal of scientific evidence to suggest that the use of carefully chosen herbal remedies and dietary supplements can help to lower blood pressure, as well as to improve the overall functioning of the heart, arteries and the entire cardiovascular system.
What herbalists have known for centuries has now been clinically proven to be a potentially effective alternative to synthetic blood pressure medication, especially if combined with a healthy diet and regular exercise.
Click HERE to view our complete list of proven natural remedies for the treatment of high blood pressure and hypertension.
