High blood pressure (hypertension) And Low Blood Pressure (hypotension)

                       

                                              High Blood Pressure


Definition


High blood pressure is a common condition in which the force of the blood against your artery walls is high enough that it may eventually cause health problems, such as heart disease.


Blood pressure is determined by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure.


You can have high blood pressure (hypertension) for years without any symptoms. Even without symptoms, damage to blood vessels and your heart continues and can be detected. Uncontrolled high blood pressure increases your risk of serious health problems, including heart attack and stroke.


High blood pressure generally develops over many years, and it affects nearly everyone eventually. Fortunately, high blood pressure can be easily detected. And once you know you have high blood pressure, you can work with your doctor to control it.

                       



             




             




                                 




                           









                   




                                  







                             

                        







                 










Symptoms


Most people with high blood pressure have no signs orsymptoms, even if blood pressure readings reach dangerously high levels.


Although a few people with early-stage high blood pressuremay have dull headaches, dizzy spells or a few more nosebleeds than normal, these signs and symptoms usually don't occur until high blood pressure has reached a severe or life-threatening stage.
When to see a doctor


You'll likely have your blood pressure taken as part of a routine doctor's appointment.


Ask your doctor for a blood pressure reading at least every two years starting at age 18. Blood pressure should be checked in both arms to determine if there is a difference. Your doctor will likely recommend more frequent readings if you've already been diagnosed with high blood pressure or other risk factors for cardiovascular disease. Children age 3 and older will usually have their blood pressure measured as a part of their yearly checkups.


If you don't regularly see your doctor, you may be able to get a free blood pressure screening at a health resource fair or other locations in your community. You can also find machines in some stores that will measure your blood pressure for free, but these machines can give you inaccurate results.










Causes


There are two types of highblood pressure.
Primary (essential) hypertension


For most adults, there's no identifiable cause of high blood pressure. This type of high blood pressure, called essential hypertension or primary hypertension, tends to develop gradually over many years.
Secondary hypertension


Some people have high blood pressure caused by an underlying condition. This type of high blood pressure, called secondary hypertension, tends to appear suddenly and cause higher blood pressure than does primary hypertension. Various conditions and medications can lead to secondary hypertension, including:
Kidney problems
Adrenal gland tumors
Thyroid problems
Certain defects in blood vessels you're born with (congenital)
Certain medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs
Illegal drugs, such as cocaine and amphetamines
Alcohol abuse or chronic alcohol use
Obstructive sleep apnea






Risk factors


High blood pressure has manyrisk factors, including:
Age. The risk of high blood pressure increases as you age. Through early middle age, or about age 45, high blood pressure is more common in men. Women are more likely to develop high blood pressure after age 65.
Race. High blood pressure is particularly common among blacks, often developing at an earlier age than it does in whites. Serious complications, such as stroke, heart attack, and kidney failure, also are more common in blacks.
Family history. High blood pressure tends to run in families.
Being overweight or obese. The more you weigh the more blood you need to supply oxygen and nutrients to your tissues. As the volume of blood circulated through your blood vessels increases, so does the pressure on your artery walls.
Not being physically active. People who are inactive tend to have higher heart rates. The higher your heart rate, the harder your heart must work with each contraction and the stronger the force on your arteries. Lack of physical activity also increases the risk of being overweight.
Using tobacco. Not only does smoking or chewing tobacco immediately raise your blood pressure temporarily, but the chemicals in tobacco can damage the lining of your artery walls. This can cause your arteries to narrow, increasing your blood pressure. Secondhand smoke also can increase your blood pressure.
Too much salt (sodium) in your diet. Too much sodium in your diet can cause your body to retain fluid, which increases blood pressure.
Too little potassium in your diet. Potassium helps balance the amount of sodium in your cells. If you don't get enough potassium in your diet or retain enough potassium, you may accumulate too much sodium in your blood.
Too little vitamin D in your diet. It's uncertain if having too little vitamin D in your diet can lead to high blood pressure. Vitamin D may affect an enzyme produced by your kidneys that affects your blood pressure.


Drinking too much alcohol. Over time, heavy drinking can damage your heart. Having more than two drinks a day for men and more than one drink a day for women may affect your blood pressure.


If you drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger.
Stress. High levels of stress can lead to a temporary increase in blood pressure. If you try to relax by eating more, using tobacco or drinking alcohol, you may only increase problems with high blood pressure.
Certain chronic conditions. Certain chronic conditions also may increase your risk of high blood pressure, such as kidney disease and sleep apnea.


Sometimes pregnancy contributes to high blood pressure, as well.


Although high blood pressure is most common in adults, children may be at risk, too. For some children, high blood pressure is caused by problems with the kidneys or heart. But for a growing number of kids, poor lifestyle habits, such as an unhealthy diet, obesity and lack of exercise, contribute to high blood pressure.


Complications
The excessive pressure on your artery walls caused by highblood pressure can damage your blood vessels, as well as organs in your body. The higher your blood pressure and the longer it goes uncontrolled, the greater the damage.


Uncontrolled high blood pressure can lead to:
Heart attack or stroke. High blood pressure can cause hardening and thickening of the arteries (atherosclerosis), which can lead to a heart attack, stroke or other complications.
Aneurysm. Increased blood pressure can cause your blood vessels to weaken and bulge, forming an aneurysm. If an aneurysm ruptures, it can be life-threatening.
Heart failure. To pump blood against the higher pressure in your vessels, your heart muscle thickens. Eventually, the thickened muscle may have a hard time pumping enough blood to meet your body's needs, which can lead to heart failure.
Weakened and narrowed blood vessels in your kidneys.This can prevent these organs from functioning normally.
Thickened, narrowed or torn blood vessels in the eyes.This can result in vision loss.


Metabolic syndrome. This syndrome is a cluster of disorders of your body's metabolism, including increased waist circumference; high triglycerides; low high-density lipoprotein (HDL); or "good," cholesterol; high blood pressure; and high insulin levels.


If you have high blood pressure, you're more likely to have other components of metabolic syndrome. The more components you have, the greater your risk of developing diabetes, heart disease or stroke.
Trouble with memory or understanding. Uncontrolled high blood pressure may also affect your ability to think, remember and learn. Trouble with memory or understanding concepts is more common in people with high blood pressure.



Test and diagnosis


To measure your blood pressure, your doctor or a specialist will usually place an inflatable arm cuff around your arm and measure your blood pressure using a pressure-measuring gauge.


A blood pressure reading, given in millimeters of mercury (mm Hg), has two numbers. The first, or upper, number measures the pressure in your arteries when your heart beats (systolic pressure). The second, or lower, number measures the pressure in your arteries between beats (diastolic pressure).


Blood pressure measurements fall into four general categories:
Normal blood pressure. Your blood pressure is normal if it's below 120/80 mm Hg. However, some doctors recommend 115/75 mm Hg as a better goal. Once blood pressure rises above 115/75 mm Hg, the risk of cardiovascular disease begins to increase.
Prehypertension. Prehypertension is a systolic pressure ranging from 120 to 139 mm Hg or a diastolic pressure ranging from 80 to 89 mm Hg. Prehypertension tends to get worse over time.
Stage 1 hypertension. Stage 1 hypertension is a systolic pressure ranging from 140 to 159 mm Hg or a diastolic pressure ranging from 90 to 99 mm Hg.
Stage 2 hypertension. More severe hypertension, stage 2 hypertension is a systolic pressure of 160 mm Hg or higher or a diastolic pressure of 100 mm Hg or higher.


Both numbers in a blood pressure reading are important. But after age 60, the systolic reading is even more significant. Isolated systolic hypertension — when diastolic pressure is normal but systolic pressure is high — is a common type of high blood pressure among people older than 60.


Your doctor will likely take two to three blood pressure readings each at three or more separate appointments before diagnosing you with high blood pressure. This is because blood pressure normally varies throughout the day, and sometimes specifically during visits to the doctor, a condition called white-coat hypertension. Your blood pressure should be measured in both arms to determine if there is a difference. Your doctor may ask you to record your blood pressure at home and at work to provide additional information.


If you have any type of high blood pressure, your doctor will review your medical history and conduct a physical examination.


Your doctor may also recommend routine tests, such as a urine test (urinalysis), blood tests and an electrocardiogram — a test that measures your heart's electrical activity. Your doctor may also recommend additional tests, such as a cholesterol test, to check for more signs of heart disease.
Taking your blood pressure at home


An important way to check if your blood pressure treatment is working, or to diagnose worsening high blood pressure, is to monitor your blood pressure at home. Home blood pressuremonitors are widely available, and you don't need a prescription to buy one. Talk to your doctor about how to get started.


Lifestyle and home remedies


Lifestyle changes can help you control and prevent high blood pressure, even if you're taking blood pressure medication. Here's what you can do:
Eat healthy foods. Try the Dietary Approaches to Stop Hypertension (DASH) diet, which emphasizes fruits, vegetables, whole grains and low-fat dairy foods. Get plenty of potassium, which can help prevent and control high blood pressure. Eat less saturated fat and total fat.


Decrease the salt in your diet. A lower sodium level — 1,500 milligrams (mg) a day — is appropriate for people 51 years of age or older, and individuals of any age who are African-American or who have hypertension, diabetes or chronic kidney disease.


Otherwise healthy people can aim for 2,300 mg a day or less. While you can reduce the amount of salt you eat by putting down the saltshaker, you should also pay attention to the amount of salt that's in the processed foods you eat, such as canned soups or frozen dinners.
Maintain a healthy weight. If you're overweight, losing even 5 pounds (2.3 kilograms) can lower your blood pressure.
Increase physical activity. Regular physical activity can help lower your blood pressure and keep your weight under control. Strive for at least 30 minutes of physical activity a day.
Limit alcohol. Even if you're healthy, alcohol can raise your blood pressure. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger.
Don't smoke. Tobacco injures blood vessel walls and speeds up the process of hardening of the arteries. If you smoke, ask your doctor to help you quit.
Manage stress. Reduce stress as much as possible. Practice healthy coping techniques, such as muscle relaxation and deep breathing. Getting plenty of sleep can help, too.


Monitor your blood pressure at home. Home blood pressuremonitoring can help you keep closer tabs on your blood pressure, show if medication is working, and even alert you and your doctor to potential complications.


If your blood pressure is under control, you may be able to make fewer visits to your doctor if you monitor your blood pressure at home.


Practice relaxation or slow, deep breathing. Practice taking deep, slow breaths to help relax. There are some devices available that can help guide your breathing for relaxation. However, it's questionable whether these devices have a significant effect on lowering your blood pressure.


                    Low Blood Pressure

Definition


Low blood pressure (hypotension) would seem to be something to strive for. However, for many people, low blood pressure can causesymptoms of dizziness and fainting. In severe cases, low blood pressure can be life-threatening.


Although blood pressure varies from person to person, a blood pressure reading of 90 millimeters of mercury (mm Hg) or lesssystolic blood pressure (the top number in a blood pressure reading) or 60 mm Hg or less diastolic blood pressure (the bottom number) is generally considered low blood pressure.


The causes of low blood pressure can range from dehydration to serious medical or surgical disorders. Low blood pressure is treatable, but it's important to find out what's causing your condition so that it can be properly treated.


Symptoms
For some people, low blood pressure can signal an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:
Dizziness or lightheadedness
Fainting (syncope)
Lack of concentration
Blurred vision
Nausea
Cold, clammy, pale skin
Rapid, shallow breathing
Fatigue
Depression
Thirst
When to see a doctor


In many instances, low blood pressure isn't serious. If you have consistently low readings but feel fine, your doctor is likely to monitor you during routine exams.


Even occasional dizziness or lightheadedness may be a relatively minor problem — the result of mild dehydration from too much time in the sun or a hot tub, for example. In these situations, it's not a matter so much of how far, but of how quickly, your blood pressure drops.


Still, it's important to see your doctor if you experience any signs or symptoms of hypotension because they sometimes can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you were doing at the time.




Causes

Blood pressure is a measurement of the pressure in your arteries during the active and resting phases of each heartbeat. Here's what the numbers mean:
Systolic pressure. The first (top) number in a blood pressure reading, this is the amount of pressure your heart generates when pumping blood through your arteries to the rest of your body.
Diastolic pressure. The second (bottom) number in a blood pressure reading, this refers to the amount of pressure in your arteries when your heart is at rest between beats.


Current guidelines identify normal blood pressure as lower than 120/80 mm Hg.


Although you can get an accurate blood pressure reading at any given time, blood pressure isn't always the same. It can vary considerably in a short amount of time — sometimes from one heartbeat to the next, depending on body position, breathing rhythm, stress level, physical condition, medications you take, what you eat and drink, and even time of day. Blood pressure is usually lowest at night and rises sharply on waking.
Blood pressure: How low can you go?


What's considered low blood pressure for you may be normal for someone else. Most doctors consider chronically low blood pressure too low only if it causes noticeable symptoms.


Some experts define low blood pressure as readings lower than 90 mm Hg systolic or 60 mm Hg diastolic — you need to have only one number in the low range for your blood pressure to be considered lower than normal. In other words, if your systolic pressure is a perfect 115, but your diastolic pressure is 50, you're considered to have lower than normal pressure.


A sudden fall in blood pressure also can be dangerous. A change of just 20 mm Hg — a drop from 110 systolic to 90 mm Hg systolic, for example — can cause dizziness and fainting when the brain fails to receive an adequate supply of blood.


And big plunges, especially those caused by uncontrolled bleeding, severe infections or allergic reactions, can be life-threatening.


Athletes and people who exercise regularly tend to have lower blood pressure and a slower heart rate than do people who aren't as fit. So, in general, do nonsmokers and people who eat a healthy diet and maintain a normal weight.


But in some rare instances, low blood pressure can be a sign of serious, even life-threatening disorders.
Conditions that can cause low blood pressure


Some medical conditions can cause low blood pressure. These include:
Pregnancy. Because a woman's circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. This is normal, and blood pressure usually returns to your pre-pregnancy level after you've given birth.


Heart problems. Some heart conditions that can lead to low blood pressure include extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure.


These conditions may cause low blood pressure because they prevent your body from being able to circulate enough blood.
Endocrine problems. Thyroid conditions — such as parathyroid disease — adrenal insufficiency (Addison's disease), low blood sugar (hypoglycemia) and, in some cases, diabetes can trigger low blood pressure.


Dehydration. When you become dehydrated, your body loses more water than it takes in. Even mild dehydration can cause weakness, dizziness and fatigue. Fever, vomiting, severe diarrhea, overuse of diuretics and strenuous exercise can all lead to dehydration.


Far more serious is hypovolemic shock, a life-threatening complication of dehydration. It occurs when low blood volume causes a sudden drop in blood pressure and a reduction in the amount of oxygen reaching your tissues. If untreated, severe hypovolemic shock can cause death within a few minutes or hours.
Blood loss. Losing a lot of blood from a major injury or internal bleeding reduces the amount of blood in your body, leading to a severe drop in blood pressure.
Severe infection (septicemia). Septicemia can happen when an infection in the body enters the bloodstream. This condition can lead to a life-threatening drop in blood pressure calledseptic shock.
Severe allergic reaction (anaphylaxis). Anaphylaxis is a severe and potentially life-threatening allergic reaction. Common triggers of anaphylaxis include foods, certain medications, insect venoms and latex. Anaphylaxis can cause breathing problems, hives, itching, a swollen throat and a drop in blood pressure.
Lack of nutrients in your diet. A lack of the vitamins B-12 and folate can cause a condition in which your body doesn't produce enough red blood cells (anemia), causing low blood pressure.

Types of low blood pressure
Doctors often break down low blood pressure (hypotension) into different categories, depending on the causes and other factors. Some types of low blood pressure include:


Low blood pressure on standing up (orthostatic, or postural, hypotension). This is a sudden drop in blood pressure when you stand up from a sitting position or if you stand up after lying down.


Ordinarily, gravity causes blood to pool in your legs whenever you stand. Your body compensates for this by increasing your heart rate and constricting blood vessels, thereby ensuring that enough blood returns to your brain.


But in people with orthostatic hypotension, this compensating mechanism fails and blood pressure falls, leading to symptoms of dizziness, lightheadedness, blurred vision and even fainting.


Orthostatic hypotension can occur for a variety of reasons, including dehydration, prolonged bed rest, pregnancy, diabetes, heart problems, burns, excessive heat, large varicose veins and certain neurological disorders.


A number of medications also can cause orthostatic hypotension, particularly drugs used to treat high blood pressure— diuretics, beta blockers, calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors — as well as antidepressants and drugs used to treat Parkinson's disease and erectile dysfunction.


Orthostatic hypotension is especially common in older adults, with as many as 20 percent of those older than age 65 experiencing orthostatic hypotension.


But orthostatic hypotension can also affect young, otherwise healthy people who stand up suddenly after sitting with their legs crossed for long periods or after working for a time in a squatting position.


Low blood pressure after eating (postprandial hypotension). Postprandial hypotension is a sudden drop in blood pressure after eating. It affects mostly older adults.


Just as gravity pulls blood to your feet when you stand, a large amount of blood flows to your digestive tract after you eat.


Ordinarily, your body counteracts this by increasing your heart rate and constricting certain blood vessels to help maintain normal blood pressure. But in some people these mechanisms fail, leading to dizziness, faintness and falls.


Postprandial hypotension is more likely to affect people with high blood pressure or autonomic nervous system disorders such as Parkinson's disease.


Lowering the dose of blood pressure drugs and eating small, low-carbohydrate meals may help reduce symptoms.


Low blood pressure from faulty brain signals (neurally mediated hypotension). This disorder causes blood pressure to drop after standing for long periods, leading to signs and symptoms such as dizziness, nausea and fainting.


Neurally mediated hypotension mostly affects young people, and it seems to occur because of a miscommunication between the heart and the brain.


When you stand for extended periods, your blood pressure falls as blood pools in your legs. Normally, your body then makes adjustments to normalize your blood pressure.


But in people with neurally mediated hypotension, nerves in the heart's left ventricle actually signal the brain that blood pressure is too high, rather than too low.


As a result, the brain lessens the heart rate, decreasing blood pressure even further. This causes more blood to pool in the legs and less blood to reach the brain, leading to lightheadedness and fainting.


Low blood pressure due to nervous system damage (multiple system atrophy with orthostatic hypotension).Also called Shy-Drager syndrome, this rare disorder causes progressive damage to the autonomic nervous system, which controls involuntary functions such as blood pressure, heart rate, breathing and digestion.


Although this condition can be associated with muscle tremors, slowed movement, problems with coordination and speech, and incontinence, its main characteristic is severe orthostatic hypotension in combination with very high blood pressure when lying down.



Risk factors


Low blood pressure (hypotension) can occur in anyone, though certain types of low blood pressure are more common depending on your age or other factors:


Age. Drops in blood pressure on standing or after eating occur primarily in adults older than 65. Orthostatic, or postural, hypotension happens after standing up, while postprandial hypotension happens after eating a meal.


Neurally mediated hypotension happens as a result of a miscommunication between the brain and heart. It primarily affects children and younger adults.
Medications. People who take certain medications, such ashigh blood pressure medications like alpha blockers, have a greater risk of low blood pressure.
Certain diseases. Parkinson's disease, diabetes and some heart conditions put you at a greater risk of developing low blood pressure.


Complications

Even moderate forms of low blood pressure can cause not only dizziness and weakness but also fainting and a risk of injury from falls.


And severely low blood pressure from any cause can deprive your body of enough oxygen to carry out its normal functions, leading to damage to your heart and brain.



Test and diagnosis


The goal in testing for low blood pressure is to find the underlying cause. This helps determine the correct treatment and identify any heart, brain or nervous system problems that may cause lower than normal readings. To reach a diagnosis, your doctor may recommend one or more of the following tests:


Blood pressure test. Blood pressure is measured with an inflatable arm cuff and a pressure-measuring gauge.


A blood pressure reading, given in millimeters of mercury (mm Hg), has two numbers. The first, or upper, number measures the pressure in your arteries when your heart beats (systolic pressure). The second, or lower, number measures the pressure in your arteries between beats (diastolic pressure).
Blood tests. These can provide information about your overall health as well as whether you have low blood sugar(hypoglycemia), high blood sugar (hyperglycemia or diabetes) or a low number of red blood cells (anemia), all of which can cause lower than normal blood pressure.


Electrocardiogram (ECG). During this painless, noninvasive test, soft, sticky patches (electrodes) are attached to the skin of your chest, arms and legs. The patches detect your heart's electrical signals while a machine records them on graph paper or displays them on a screen.


An ECG, which can be performed in your doctor's office, detects irregularities in your heart rhythm, structural abnormalities in your heart, and problems with the supply of blood and oxygen to your heart muscle. It can also tell if you're having a heart attack or if you've had a heart attack in the past.


Sometimes, heart rhythm abnormalities come and go, and an ECG won't find any problems. If this happens, you may be asked to wear a 24-hour Holter monitor to record your heart's electrical activity as you go about your daily routine.


Echocardiogram. This noninvasive exam, which includes an ultrasound of your chest, shows detailed images of your heart's structure and function.


Ultrasound waves are transmitted, and their echoes are recorded with a device called a transducer, which is held outside your body. A computer uses the information from the transducer to create moving images on a video monitor.


Stress test. Some heart problems that can cause low blood pressure are easier to diagnose when your heart is working harder than when it's at rest. During a stress test, you'll exercise, such as walking on a treadmill. You may be given medication to make your heart work harder if you're unable to exercise.


When your heart is working harder, your heart will be monitored with electrocardiography or echocardiography. Your blood pressure also may be monitored.
Valsalva maneuver. This noninvasive test checks the functioning of your autonomic nervous system by analyzing your heart rate and blood pressure after several cycles of a type of deep breathing: You take a deep breath and then force the air out through your lips, as if you were trying to blow up a stiff balloon.


Tilt table test. If you have low blood pressure on standing, or from faulty brain signals (neurally mediated hypotension), your doctor may suggest a tilt table test, which evaluates how your body reacts to changes in position.


During the test, you lie on a table that's tilted to raise the upper part of your body, which simulates the movement from horizontal to a standing position.


Lifestyle and home remedie


Depending on the reason for your low blood pressure, you may be able to take certain steps to help reduce or even prevent symptoms. Some suggestions include:
Drink more water, less alcohol. Alcohol is dehydrating and can lower blood pressure, even if you drink in moderation. Water, on the other hand, combats dehydration and increases blood volume.


Follow a healthy diet. Get all the nutrients you need for good health by focusing on a variety of foods, including whole grains, fruits, vegetables, and lean chicken and fish.


If your doctor suggests using more salt but you don't like a lot of salt on your food, try using natural soy sauce or adding dry soup mixes to dips and dressings.


Go slowly when changing body positions. You may be able to reduce the dizziness and lightheadedness that occur with low blood pressure on standing by taking it easy when you move from a prone to a standing position.


Before getting out of bed in the morning, breathe deeply for a few minutes and then slowly sit up before standing. Sleeping with the head of your bed slightly elevated also can help fight the effects of gravity.


If you begin to get symptoms while standing, cross your thighs in a scissors fashion and squeeze, or put one foot on a ledge or chair and lean as far forward as possible. These maneuvers encourage blood to flow from your legs to your heart.


Eat small, low-carb meals. To help prevent blood pressure from dropping sharply after meals, eat small portions several times a day and limit high-carbohydrate foods such as potatoes, rice, pasta and bread.


Your doctor also may recommend drinking caffeinated coffee or tea with meals to temporarily raise blood pressure. But because caffeine can cause other problems, check with your doctor before drinking more caffeinated beverages.