Feb 7 - 13, 2011
Blood pressure is the force created by the heart as it pushes blood into the arteries and the circulatory system. When the heart pumps, it causes blood to flow through the arteries and into the arterioles. As the blood goes through the arterioles, the arterioles either contract or expand altering both the amount of blood flow and the resistance to blood flow. If the arterioles remain in a contracted form, they create high blood pressure. The heart must then pump harder because the arterioles are exerting a greater resistance to blood flow.
The term blood pressure usually refers to the pressure measured at a person's upper arm. It is measured on the inside of an elbow at the brachial artery, which is the upper arm's major blood vessel that carries blood away from the heart. A person's BP is usually expressed in terms of the systolic pressure over diastolic pressure, for example 120/80.
What is "normal" blood pressure?
There are several categories of blood pressure, including:
* Normal: Less than 120/80
* Pre-hypertension: 120-139/80-89
* Stage 1 high blood pressure: 140-159/90-99
* Stage 2 high blood pressure: 160 and above/100 and above
Average blood pressure in (mmHg):
* 1 year: 95/65
* 6 - 9 years: 100/65
* Adults: 110/65 - 140/90
LOW BLOOD PRESSURE HYPOTENSION
Blood pressure that is too low is known as hypotension. The similarity in pronunciation with hypertension can cause confusion. Hypotension is a medical concern only if it causes signs or symptoms, such as dizziness, fainting, or in extreme cases, shock. When arterial pressure and blood flow decrease beyond a certain point, the perfusion of the brain becomes critically decreased (i.e., the blood supply is not sufficient), causing lightheadedness, dizziness, weakness or fainting.
Sometimes the arterial pressure drops significantly when a patient stands up from sitting. This is known as orthostatic hypotension (postural hypotension); gravity reduces the rate of blood return from the body veins below the heart back to the heart, thus reducing stroke volume and cardiac output.
When people are healthy, the veins below their heart quickly constrict and the heart rate increases to minimize and compensate for the gravity effect. This is carried out involuntarily by the autonomic nervous system. The system usually requires a few seconds to fully adjust and if the compensations are too slow or inadequate, the individual will suffer reduced blood flow to the brain, dizziness, and potential blackout. Repositioning the body perpendicular to gravity largely eliminates the problem.
Other causes of low arterial pressure include:
* Hemorrhage - blood loss
* Toxins including toxic doses of BP medicine
* Hormonal abnormalities, such as Addison's disease
* Eating disorders, particularly anorexia nervosa and bulimia
Shock is a complex condition, which leads to critically decreased perfusion. The usual mechanisms are loss of blood volume, pooling of blood within the veins reducing adequate return to the heart and/or low effective heart pumping. Low arterial pressure, especially low pulse pressure, is a sign of shock, and contributes to and reflects decreased perfusion. If there is a significant difference in the pressure from one arm to the other, that may indicate a narrowing (for example, due to aortic coarctation, aortic dissection, thrombosis or embolism) of an artery.
HIGH BLOOD PRESSURE HYPERTENSION
Hypertension is also known as high blood pressure. This is most popular and common ailment arising out of heart. Most of the human beings are affected by this condition. Hypertension can be defined that the pressure or force exerted against the arterial walls while the heart pumps each time and the maximum pressure measured in this process is called systolic pressure and the minimum pressure in between the beats is called the diastolic pressure. This condition is attained in every hypertensive person slowly and it reaches the maximum pressure. In the initial stage of this condition, one does not show or feel any symptoms. They develop symptoms only in the later stages. The common symptoms are giddiness in most of the cases, headaches of mild or severe form, nose bleeding in rare cases, dizzy spells.
Somebody doesn't develop symptoms even in the advanced stages and it is noticeable only during regular health checkups. The normal human blood pressure is 120/80 mm Hg. When it is up to 140/90, it is called transitional. Up to 160/100, it can be called as essential hypertension and it also comes under transitional.
When it goes and settles beyond 160/100 mm Hg. It is typically called hypertension and it is a permanent condition. Hypertension is caused in individuals due to various causes such as heredity, hormone changes linked with kidney activity, obesity, excess salt intake pattern, low potassium intake and alcohol intake.
TYPES OF HYPERTENSION:
Arterial hypertension can be an indicator of other problems and may have long-term adverse effects. Sometimes, it can be an acute problem, for example, hypertensive emergency. All levels of arterial pressure put mechanical stress on the arterial walls. Higher pressures increase heart workload and progression of unhealthy tissue growth (atheroma) that develops within the walls of arteries. The higher the pressure, the more stress that is present and the more atheroma tend to progress and the heart muscle tends to thicken, enlarge and become weaker over time.
Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysms, and is the leading cause of chronic renal failure. Even moderate elevation of arterial pressure leads to shortened life expectancy. At severely high pressures, mean arterial pressures 50 per cent or more above average, a person can expect to live no more than a few years unless appropriately treated.
In the past, most attention was paid to diastolic pressure; but now a days, it is recognized that both high systolic pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk factors. In some cases, it appears that a decrease in excessive diastolic pressure can actually increase risk, due probably to the increased difference between systolic and diastolic pressures.
What causes high blood pressure? The exact causes of high blood pressure are not known. Several factors and conditions may play a role in its development, including:
* Being overweight or obese
* Lack of physical activity
* Too much salt in the diet
* Too much alcohol consumption (more than 1 to 2 drinks per day)
* Older age
* Family history of high blood pressure
* Chronic kidney disease
* Adrenal and thyroid disorders
HOW IS BLOOD PRESSURE MEASURED?
Blood pressure is measured at two points, a high point and a low point. The high point is the point at which the heart contracts to empty its blood into the circulation, called systole. The low point is the point at which the heart relaxes to fill with blood returned by the circulation, called diastole. Pressure is measured in millimeters (mm) of mercury by an instrument called a sphygmomanometer.
In humans, blood pressure does not vary greatly. In healthy persons, blood pressure increases from about 80/45 in infants, to about 120/80 at age 30, to about 140/85 at age 40 and over. Blood pressure increases with age because the arteries loose elasticity. Abnormally, high blood pressure (hypertension) is considered a contributory cause of arteriosclerosis. Abnormally low blood pressure (hypotension) is observed in infectious and wasting diseases, hemorrhage, and persons who have collapsed.
DOES BLOOD PRESSURE STAY THE SAME?
No. Your blood pressure varies all the time to meet your body's needs. The pressure will be different when you get up in the morning, to when you are relaxing, exercising, or sleeping. Blood pressure is usually at its highest when we exercise, and lowest when we sleep. Blood pressure can also rise due to anxiety, excitement, activity, or nervousness. In general, blood pressure remains fairly constant throughout the day.
Medications for blood pressure should be prescribed by and taken under the direction of a doctor.
Diuretics: Commonly called "water pills," they lower blood pressure by reducing the body's sodium and water volume.
Vasodilators: These drugs relax the muscles in the blood vessel walls, causing them to dilate, or widen.
HOW IS BLOOD PRESSURE CONTROLLED?
Largely the nervous system regulates blood pressure. Hemoglobin, the iron-protein compound that gives blood its red color, also plays a role in regulating blood pressure. However, hemoglobin's affect is usually localized and is not very useful when trying to control blood pressure on a large scale. Hemoglobin contains nitric oxide, a gas that relaxes the blood vessel walls, thus increasing blood flow. It controls the expansion and contraction of blood vessels, and thus blood pressure, by regulating the amount of nitric oxide to which the vessels are exposed. There are many ways to decrease blood pressure. Blood pressure can be decreased if a person exercises, doesn't smoke, limits salt intake, limits alcohol intake and if obese, loses weight. Individuals who are very active have a lower risk of getting high blood pressure (20 to 50 per cent) than people who are not active.
Individuals with high blood pressure can be given medication to lower their blood pressure. Mild cases of blood pressure can be treated through behavior modification like changing diet and increasing exercise. More severe cases of hypertension require medications like diuretics and beta blockers. Diuretics rid the body of excess fluids and salt. Beta-blockers reduce the heart rate and the heart's output of blood.
Who is at risk for high blood pressure? In the early and middle adult years, men have high blood pressure more often than women. But, as men and women age, the reverse is true. Unfortunately, more than half of all Americans over age 65 have high blood pressure.
High blood pressure is a risk for both heart disease and stroke. Unfortunately, high blood pressure usually has no specific symptoms and no early warning signs. It directly increases the risk of heart disease. High blood pressure is a risk for heart disease because the heart is working harder than normal thus putting the heart and the arteries under a greater strain. When the heart is forced to work harder for long periods, the heart becomes enlarged. A heart that is slightly enlarged may function okay but a severely enlarged heart has a hard time pumping a sufficient amount of blood. High blood pressure is also a risk for strokes.
High blood pressure and kidney disease are closely related. One mechanism for this is the production of a hormone called 'renin' by the kidneys. If the kidneys are not functioning properly, renin can be produced inappropriately, raising the blood pressure. If high blood pressure is left unchecked, it can cause blood vessels in the kidneys to become thickened and narrowed, possibly leading to reduced blood supply and reduced kidney function.
Blood pressure as a tool: Blood pressure is an important diagnostic index, especially of circulatory function. It is an important diagnostic index for many reasons. Firstly, any condition that dilates or contracts the blood vessels or affects their elasticity, affects the blood pressure. Secondly, any disease of the heart that interferes with its pumping power, affects the blood pressure. In a healthy animal, the blood pressure normal for its species is maintained within a certain range with great constancy. Thus, if blood pressure is abnormally low or high, it usually indicates that greater health problems are present.
There are two risk factors for high blood pressure. 1. Weight 2. Salt. These are the two factors involved in forming and maintaining the high blood pressure. To control the blood pressure in the normal range, it is possible to select a food ("high blood pressure diet") that will keep up the body weight in normal or will reduce if necessary and salt intake within the norms of about of 2400 mg per day. This will enable the body to maintain or reduce the high blood pressure and hence it is well known fact that food plays an important role in lowering the high blood pressure. In fact, dieting and food is a large subject that cannot be covered in a small detail here.
High blood pressure is one of the serious cardiac diseases that can lead to stroke, heart and kidney failure. This is common among aged one and it contributes to millions of death all over the world. Although most of the people is unaware of it and earlier detection of this disease will help in controlling it. At the same time, it is important that every hypertensive should know about the foods that cause high blood pressure. When a person is diagnosed for hypertension, he is prescribed with medication. But it is most important that he should understand and practice the life style changes which include weight management, low salt diet, controlled physical activity and low alcohol intake. It is also true that most of the complications that occur in this condition is because of the food they intake without any control.
THERE ARE FIVE TYPES OF FOODS THAT SHOULD BE AVOIDED.
1. Processed salt (sodium chloride) is the substance that is able to enhance or induce the blood pressure when taken in large quantity/too much along with food. Really, salt is very essential for our body's metabolism and it is harmful only when it is taken in high volume. The good alternative for processed or iodized salt is sea salt that can be used and the usage of the iodized salt to be reduced.
2. Some foods that we purchase in readily made condition are processed and treated in laboratory with hydrogenated oil. Hence, it should be avoided. If it is taken regularly, it causes high blood pressure. So this type of food should be avoided. And, when food is purchased everyone should check whether it is processed with the hydrogenated oil by seeing the labels that contain more about the food preparation.
3. Avoid any kind of fatty food or foods that are high in Tran's fat. It is well known fact that every diary product is having more fat than other food.
4. Toxic substances and chemicals are mostly contained in red meat, which causes high blood pressure and hence red meat should be avoided.
5. Sugar is the important factor that causes obesity and obesity in turn causes high blood pressure. Hence, it should be avoided.
OTHER THINGS TO BE AVOIDED.
Fried foods alike fatty foods are also causing high blood pressure. Cooking is to be done with oils like olive oil. Fatty meats are the most causative factor that induces high blood pressure. The fat content of the meat forms as deposits on the arterial walls and it causes reduced blood flow and high blood pressure. An alternative to this fatty meat, lean meat can be used.