Easing the pressure: the ins and outs of hypertension.
The heart is responsible for pumping blood through the three types of blood vessels in the body: the arteries, the veins, and the capillaries. The arteries carry oxygen-rich blood away from the heart to every part of the body; the veins carry it back to the heart, where it is sent into the lungs to be oxygenated; and the capillaries connect the two.
For every beat of the heart, blood vessels expand and contract as blood is forced through them. The veins are used to measure blood pressure, because the pressure is usually greater in these vessels than in the arteries.
Systolic pressure, a measurement of the contraction of the chambers of the heart, indicates the highest arterial blood pressure reached during a heartbeat. It is the top number in a standard blood pressure reading.
Diastolic pressure, a measurement of the relaxation of the heart, indicates the lowest arterial blood pressure reached during a heartbeat. It is the bottom number in a standard blood pressure reading.
Both systolic and diastolic pressure readings are important, but systolic pressure should be watched more carefully in people over 50 years of age.
What is hypertension?
Hypertension, or high blood pressure, is a common and sometimes misunderstood medical condition. Characterized by elevated blood pressure, it is diagnosed when systolic pressure is greater than 140 millimeters of mercury (mm. Hg.) and diastolic pressure is greater than 90 mm. Hg.
Blood pressure can rise for a variety of reasons, such as an increase in the pumping action of the heart, an increase in the amount of circulated blood, or a decrease in the overall capacity of the vessels. In layman's terms, elevated blood pressure is a sign that the heart is working harder than it should have to in order to keep the blood flowing normally.
A single elevated blood pressure reading is usually not cause for alarm. Blood pressure varies during the day, and it can even vary, depending on the patient's environment. Because of this, an elevated blood pressure reading must be taken three separate times, with each measurement at least one week apart, in order to receive a clinical diagnosis of hypertension.
What are the different types of hypertension?
Although hypertension is often used as a catchall phrase for elevated blood pressure, there is more than one type.
Essential hypertension refers to a case of elevated blood pressure with no specific medical cause.
Secondary hypertension is an elevated blood pressure caused by another problem in the body, such as kidney disease or certain tumors.
Prehypertension, a relatively new classification, refers to blood pressure that is not quite elevated but is higher than normal. The range for prehypertension is a systolic pressure of 120 to 139 mm. Hg. and a diastolic pressure of 80 to 89 mm. Hg.
Exercise hypertension refers to an excessive rise in blood pressure during physical activity. Although exercise is often recommended to help lower blood pressure, some people may experience sudden and temporary spikes in blood pressure while exercising. A rise in systolic pressure to 200 mm. Hg. is referred to as pathological. A rise to over 220 requires medication to control.
What causes hypertension?
Ordinary hypertension is only rarely attributable to a single cause. Combinations of genetics, lifestyle, stress levels, and diet are the most likely culprits. There are no symptoms when blood pressure elevation is developing. This is why the term "silent killer" has been applied to the disease so often.
Essential hypertension can develop for a variety of reasons. Diet is a well-known factor. Studies have shown that societies that consume a large amount of salt in their diet--such as the United States--have a higher incidence of hypertension. It is believed that for some patients, the kidneys cannot handle the excess salt, which leads to elevated blood pressure. Societies with a low intake of salt tend to have a low incidence of hypertension. Although salt and sodium are often considered interchangeable terms, salt is only 60 percent sodium; most ingredient labels refer to sodium but not salt.
A plant-based diet can also aid in lowering blood pressure. Excessive salt in the diet can cause the fluid volume of the blood to increase, therefore resulting in a rise in blood pressure. Because plant-based foods have no added salt, the excess fluid volume can be reduced naturally.
Genetics can also play a part in the risk of hypertension. Hypertension diagnoses can be prevalent in a family tree, but it is not clear whether that is because of shared genes or a shared lifestyle. Obesity, inactivity, cigarette smoking, and alcohol consumption are all lifestyle components that can lead to hypertension. They are also activities that can be passed down through the generations.
About 10 percent of all hypertension diagnoses are secondary hypertension, which can be traced to a specific cause, for example, a narrowing of the arteries that lead to the kidneys, sleep apnea, insulin resistance, kidney disease, endocrine abnormalities such as overactive adrenal glands, pregnancy, and medications such as some oral contraceptives or estrogen-replacement therapies.
What kind of damage can result from high blood pressure?
Hypertension is not a death sentence, but chronic hypertension can result in serious damage to the cerebrovascular system, which can cause strokes or other brain incidents; heart attacks; heart failures damage to the eyes and kidneys; and other end-organ damage.
How can hypertension be treated?
After a diagnosis of high blood pressure is made, treatments may vary, depending on the individual and the severity of the case. The first steps often involve lifestyle modification. If the patient has a history of high-risk behaviors such as smoking or high salt intake, those behaviors must be eliminated. Quitting smoking is necessary to alleviate the risk of other problems caused by hypertension, such as stroke or heart attack.
Weight loss and regular exercise are staples of treatment, along with a diet rich in fruits and vegetables, a diet low in dairy, fat, and a low-sodium diet. A study conducted by John McDougall, M.D., author of several books about reducing blood pressure, showed that a diet of moderately low-sodium, vegetarian foods, combined with moderate exercise, reduced systolic blood pressure by an average 17 points and diastolic pressure by an average of 13 points. Medications were found to reduce blood pressure by 12 and 6 points, respectively.
Diet and exercise alone are often enough to help patients control mild to moderate hypertension, but drugs may be needed in more severe cases.
A variety of anti-hypertensive drugs are used are available. Angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor antagonists (ARBs), peripheral vasodilators, alpha and beta blockers, and diuretics are commonly prescribed, either alone or in combination. The aim of the drug treatment is to lower blood pressure to less than 140 over 90 mm. Hg.
What are some of the side effects of drugs?
There are certain dangers to taking prescription drugs for high blood pressure, and it is important to speak with your physician to weigh the benefits and the risks.
Peripheral vasodilators, for example, may cause dizziness and a rapid lowering of the blood pressure first thing in the morning. ACE inhibitors are generally well tolerated, but in some cases they can cause dangerous reactions, such as shortness of breath, angioedema, and persistent cough. Diuretics can cause potassium depletion, so it is necessary to take supplements with these agents. Care should be taken, however, because too much potassium can also raise blood pressure.
Beta blockers are thought to cause a large number of adverse reactions, such as an abnormal heart rate. A study published in the British Medical Journal (June 2006) showed that there is no general consensus as to whether beta blockers are safe to use. A variety of disparate outcomes indicate that it is unclear whether beta blockers or other variables are responsible for the number of adverse effects.
Some blood pressure medications can cause confusion and a mental state that can resemble dementia. It is important to discuss all medications with your physician.
It is not recommended that women breast-feed while taking anti-hypertensive agents, because they can be harmful to infants. A study published in the New England Journal of Medicine (June 8, 2006) showed that women who took ACE inhibitors in the first trimester of their pregnancy had a greater risk of giving birth to babies with congenital birth defects of the heart and central nervous system.
Another study, published by the American Diabetes Association, showed that use of a thiazide diuretic or beta blocker may increase the risk of type 2 diabetes.
Can low blood pressure also be a problem?
Although high blood pressure is undesirable and dangerous, low blood pressure (hypotension) is also something to avoid.
Hypotension can result from many conditions, such as reduced blood volume, decreased heart output, and excessive constriction of the blood vessels. Symptoms of hypotension include dizziness, shortness of breath, irregular heartbeat, headache, stiff neck, loss of appetite, seizures, and prolonged fatigue. Because these symptoms can also be construed as representing other problems, it is necessary to keep a constant dialogue with your physician regarding your health.
Postural hypotension is a common form of temporary low blood pressure resulting from a change in the position of the body. It is most often experienced when waking up in the morning and getting out of bed too quickly.
How often should people get their blood pressure checked?
Blood pressure should be checked occasionally, even in children as young as age two. After the age of 21, blood pressure should be checked, at a minimum, once every two years; however, it is in a person's best interest to have it checked more often than that. People who are inactive, consume salty foods, smoke, drink alcohol, or have a family history of high blood pressure should be especially vigilant in scheduling check-ups.
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|Title Annotation:||blood pressure|
|Publication:||Nutrition Health Review|
|Date:||Dec 22, 2005|
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