The disease
Healthy blood pressure
Before we can understand the harmful problems related to high blood pressure, it is important to have a basic understanding of how a normal, healthy body functions. To this end, we will examine the workings of the cardiovascular system.
The cardiovascular system is made up of the heart and blood vessels. The heart is a very powerful muscular pump that delivers blood to the organs, tissues, and cells throughout the body. The blood sends oxygen and nutrients that our cells need to live and removes the carbon dioxide and other wastes that cells produce. From the heart, oxygen-rich blood is circulated through a vast network of arteries, arterioles, and capillaries, and oxygen-poor blood is pushed back to the heart through venules and veins.
As mentioned earlier, blood pressure is the force that blood exerts against the arteries as it circulates throughout the body. The flow of blood around the body is not constant, but is based on the beats of the pumping heart. On average, about two ounces of blood per heartbeat is pumped through the left ventricle of the heart and into the 60,000-mile- (96,500-kilometer-) long network of blood vessels that make up the human body.
It is also important to note that blood pressure does not stay the same all the time and is based on the activities people do (and how hard or rapidly their hearts are pumping). For example, the heart muscle can pump nearly three times faster during periods of exercise as compared to times of rest. The heart pauses, or rests, between beats in order to prepare itself for the next beat.
Using a sphygniomanometer, or blood pressure cuff, doctors measure two key blood pressure numbers — the systolic pressure and diastolic pressure. The systolic pressure shows the highest pressure in the arteries. This is when the blood is forcefully pumped out of the heart and into the blood vessels during a heartbeat. The diastolic pressure represents the lowest pressure in the arteries. This is when the heart pauses or relaxes between beats.
The numbers that result from a reading usually come in the form of 100 mmHg (millimeters of mercury) over 70 mmHg, or 100/70 mmHg. The higher number represents the systolic pressure (heart pumping) and the lower represents the diastolic pressure (heart resting). A consistent measurement of 140/90 mmHg indicates that the heart is pumping harder than it should and that the person has high blood pressure. The optimal blood pressure reading for adults is 119/79 mmHg or lower.
Blood pressure problems
Hypertension is another term for high blood pressure. It is a condition in which blood is pushed through the body’s blood vessels at greater force than normal. There are three main types of hypertension:
Primary hypertension (or “essential hypertension”) — This form of high blood pressure is the most common, affecting over 90% of those people 45 years old and over who have hypertension. While there is no known cause, there are a number of factors that contribute to its development, including age, heredity, lifestyle, diet, ethnicity, and more.
Secondary hypertension (or “non-essential hypertension”) — Unlike primary hypertension, this form of high blood pressure can be determined by a specific cause. Among the possible short-term causes are pregnancy and the use of certain types of medication. The long-term causes include kidney disorders and head injuries. This type of hypertension accounts for nearly 10% of all high blood pressure cases.
When the specific cause is identified and properly treated, blood pressure often returns to normal levels.
Isolated systolic hypertension (ISH) — This form of high blood pressure is most common in older people, affecting over 65% of people more than 60 years of age. ISH comes with no symptoms, so many people may have it and do not know it. ISH is characterized by high pressure levels when the heart is beating (systolic), but normalized levels between beats, when the heart is resting (diastolic). This large gap between pressure levels can lead to a straining of the arteries.
Symptoms of high blood pressure
Unlike many other conditions, high blood pressure often causes no symptoms. However, when symptoms do arise, it means that blood pressure is too high, often causing damage to such critical organs as the heart or kidneys. In the most severe cases, when symptoms can arise, they might come in the form of:
- headaches
- excessive perspiration (sweating)
- chest pains
- muscle tremors
- nosebleeds
- fatigue, weakness
- nausea, vomiting
- heart palpitations
- vision problems
- blood in urine
- confusion
Low blood pressure — Is it ever a problem?
Though generally regarded as a good thing, a person’s blood pressure can be too low and potentially harmful. There may be no symptoms associated with low blood pressure, and, in certain cases, it may actually be desirable. When blood pressure drops below 90/60, however, it indicates that there may not be enough blood flowing to the heart, brain, kidneys, and other major organs. Causes may include heart disease, dehydration, gastrointestinal bleeding, and the use or allergic reaction to certain medications. Most common with the elderly, sudden drops in blood pressure may lead to symptoms like fatigue, anxiety, depression, or dizziness — especially upon making a sudden change in body movement. In rare cases, treatment is required, usually in the form of medication that helps alter blood pressure receptors or constrict arteries to reduce the likelihood of sudden or frequent drops in blood pressure.
How high blood pressure affects the body
High blood pressure affects the body in a variety of ways. The most critical effect is the strain it can put on the heart. High blood pressure also damages blood vessels and, if left untreated over time, can greatly impair the heart, brain, kidneys, and eyes. With few or no noticeable symptoms, this silent and potentially deadly condition can lead to severe physical damage well before a person understands what is happening and seeks medical treatment.
High blood pressure is a serious risk factor for different forms of heart disease, including congestive heart failure, which most commonly affects the elderly. As high blood pressure stretches and damages the heart from overwork, it also strains the blood vessels and hardens the arteries, making them thicker and less flexible, greatly increasing the chance of heart attack and stroke. Without diagnosis or treatment, the kidneys can become stressed and damaged, hurting their ability to clean the blood and potentially leading to kidney failure. Among the temporary or permanent vision problems that can result are optic nerve swelling and bleeding in the retina.
To avoid these and other life-threatening complications, doctors recommend having blood pressure checked at least once a year, so patients who have high blood pressure can be treated effectively. This is important because research shows that — compared to people who have received treatment for high blood pressure — those who have hypertension but do not know it are about 6 times more likely to have congestive heart failure, 7 times more likely to have a stroke, and 3 times more likely to have coronary artery disease. Since high blood pressure has virtually no symptoms until it becomes severe, it is especially important for people to monitor and control their blood pressure on an ongoing basis.
Causes of high blood pressure
Doctors and researchers have not been able to determine a specific cause of high blood pressure. Moreover, the cause of hypertension is unknown in 90 to 95 percent of the cases. Since no single cause seems apparent, treatment for the condition has been based on keeping blood pressure at normal levels or under control. This involves identifying the specific risk factors that, when combined, can greatly increase a person’s chance of developing high blood pressure. These risk factors include:
| Controllable | Uncontrollable |
| high salt intake | heredity |
| obesity | race |
| excessive alcohol use | gender |
| lack of exercise | age |
| use of certain medications | |
| drug or chemical use | |
| diabetes | |
| kidney disease | |
| stress |
Salt has been found to be a risk factor because too much of it can raise fluid levels in the bloodstream, forcing the heart to work harder and blood pressure levels to rise. This is particularly true if the kidneys, which regulate sodium (salt) and water levels in the body, are not working properly. Obesity is another key risk factor. When a person gains weight, his or her blood levels also increase, causing the heart to pump more blood. The additional weight also causes a person’s blood pressure to elevate because it increases cholesterol levels, leading to a further straining and hardening of the blood vessels and heart. Excessive alcohol consumption can also reduce the heart’s ability to function properly, increasing blood pressure levels. Drinking too much alcohol can also make high blood pressure medication less effective.
Luckily, as suggested by the “controllable” factors above, there is much that people can do throughout their lives to keep their blood pressure at a healthy level. Unfortunately, high blood pressure doesn’t affect all people in the same way. For example, African Americans are much more likely to develop the condition earlier and more severely than whites. Also, in terms of gender, men have a greater chance of developing it between the ages of 35 to 55, whereas women are more likely to develop it after the age of 75. What is clear, however, is that as people age, they increase their chances of developing high blood pressure.
A Closer Look at Stress and Emotions
Blood pressure is known to change throughout the day, depending on one’s activities or emotional state of mind. People who have a lot of stress in their lives — or who suffer from emotional conditions like depression or anxiety — are thought to have at least twice the risk of developing high blood pressure than others. This is because the stress hormone, cortisol, is released from the adrenal glands in greater amounts — causing blood pressure to increase — when a person experiences short-term or long-term stress. Like adrenaline, cortisol levels rise when a person is under stress. When a person’s “stress hormone” levels are elevated on a consistent basis, it can lead to a variety of health problems, from depression to high blood pressure to cancer.
Different forms of stress may also prompt people to escape their troubles by overeating, smoking, or abusing alcohol, all of which cause blood pressure to rise. Making gradual lifestyle changes that reduce stress will help to control or lower blood pressure over the long run.
Health problems from high blood pressure
IMPORTANT NOTE: The following complications of high blood pressure described below can be avoided or delayed through prevention and treatment. (See the section on care beginning on page 25.)
Stroke. High blood pressure is a leading cause for stroke, which occurs when blood has trouble flowing to the brain. High blood pressure can make a blood vessel rupture, causing a hemorrhage (bleeding) in the brain. Strokes, (or “brain attacks”) are also caused by blood clots and narrowing of the arteries (atherosclerosis). They can lead to such complications as the inability to speak, brain damage, paralysis, and death. Stroke is the third leading cause of death in the United States, accounting for 1 out of every 15 deaths. It is important for high blood pressure patients in particular to monitor their health and get effective treatment for the condition before it leads to a stroke — the risk of which doubles every 10 years after the age of 35.
Kidney Disease. The kidneys help to keep blood pressure levels regular by cleaning the blood of extra fluids and wastes. When a person develops high blood pressure, the kidneys can become damaged. When the kidneys are no longer able to function properly, the extra fluids and wastes that remain in the blood can lead to even higher blood pressure levels and, ultimately, illness. If left untreated, a person suffering from kidney disease may need a kidney transplant or dialysis treatment, which is the use of a machine to help the kidneys function and clean blood. High blood pressure is the second leading cause of kidney failure, and leads to over 15,000 new cases in the U.S every year. Research has also shown that between 20 to 25 percent of patients who must undergo dialysis first had “slightly elevated blood pressure” that had been untreated. Early and effective treatment of high blood pressure can help to prevent the occurrence of kidney disease.
Vision Problems. Vision loss or blindness can result from optic nerve damage that is brought on by high blood pressure. The condition can also lead to bleeding in the retina, the light-sensing part of the eye. This disease is called retinopathy, which can result in partial or complete blindness. Early detection and treatment can help to prevent vision loss brought on by high blood pressure.
Hardened Arteries. Atherosclerosis, or a hardening and thickening of the arteries, can result from high blood pressure. Hardened arteries can lead to a greater buildup of fats and cholesterol in the arteries and blood vessels, causing the heart to enlarge and weaken because it is forced to pump harder. This disease can block the proper flow of blood and oxygen that the heart, brain, and vital organs need to work properly. Blood clots may also form in an artery, blocking the flow of blood entirely. While considered a slow and advancing disease that mainly affects the aged, atherosclerosis (also called arteriosclerosis) may result in a heart attack or stroke if left untreated over time. In addition to high blood pressure, other risk factors that contribute to the progression of this disease include smoking, diabetes, obesity, and family history.
Heart Attack. As previously noted, hypertension can contribute to the hardening of arteries, which can lead to a heart attack. In order to function properly, the heart muscle itself needs a continuous supply of oxygen-rich blood. When arteries become narrowed or blocked, this vital flow becomes lessened, causing muscle damage and angina (chest pains). Heart attacks result when arteries and the flow of blood to the heart become completely blocked. In general, any disruption in the workings of the heart is life threatening and in need of prompt medical attention.
Heart Failure. Another aspect of the toll that high blood pressure can have on the heart is in the form of heart failure. As previously mentioned, the heart can be forced to work harder due to complications of high blood pressure and atherosclerosis. Under these unhealthy, untreated conditions, the heart begins to stretch and enlarge (either partially or as a whole). Eventually, the heart fails to function effectively — either too much, not often enough, or irregularly — and ultimately results in congestive heart failure. This disorder may involve a failing of the entire heart or just one side of it. When the left side of the heart fails, blood and other fluids get backed up in the lungs. The first signs of this condition are breathing problems, such as shortness of breath. When the right side fails, blood may back up into other areas of the body as the veins fill and leak fluid into the surrounding tissue. Symptoms of right-side failure include fatigue, indigestion, liver damage, and swelling in the legs.
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