Hypertension Defined
Hypertension is the technical medical name for high blood pressure. “Blood pressure” means the pressure against the walls of arteries of blood as it travels through them pumped by the heart. The arteries are the tubes, large and small, that carry oxygen-rich blood to all the parts of the body.
A description of hypertension
Because of the pump action of the heart, blood flowing along the arteries pushes against their inner walls: the greater the pushing force, the higher the blood pressure. The size, or diameter, of the smaller arteries can also have an effect on overall blood pressure. The walls are muscular, and when they are relaxed they dilate or enlarge the opening of the tube through which the blood is passing, lowering the pressure. Conversely, when they tighten, the arterial diameter decreases,and blood pressure goes up.
In the cycle of heart action, the highest blood pressure occurs when the heart contracts, or “beats”, to push blood into the arteries. When the heart relaxes so that its chambers can refill with blood, then the pressure is lowest. The high pressure at the “beat” is the “systolic” pressure, and the low, relaxed pressure is the “diastolic” pressure. When you have your blood pressure measured, the reading shows the systolic first, the diastolic second, measured in millimeters of mercury (abbreviated as mm Hg). So a systolic pressure of 120 and a diastolic pressure of 80 will be recorded as 120/80 mm Hg. Any blood pressure reading above 140/90 is considered high for an adult by the American Heart Association.
One of the factors making hypertension a serious health problem is the fact that it has no symptoms, so that many people have it and are unaware of it. It is estimated that, in the US, approximately 50 million people sixty years old or older have hypertension. Men are more likely to have it than women, and older people than younger. After age 65, the percentage of those with hypertension is over 50%. African Americans are also more likely to have high blood pressure than white Americans. The condition is serious because it puts people at greater risk than normal for heart disease and other dangerous conditions. The complications can be avoided by getting regular blood pressure readings, and treating hypertension immediately if it should develop.
Untreated hypertension may lead to other serious conditions, including:
- Arteriosclerosis (atherosclerosis)
- Heart attack
- Stroke
- Blindness
- Heart enlargement
- Damage to the kidneys
Arteriosclerosis or atherosclerosis is what is commonly called hardening of the arteries. A normal artery wall has an elastic layer of tissue and muscle that lets it widen and narrow as pulsing blood flows through. The effect of continuous high blood pressure can be a thickening and hardening of the walls, reducing the elasticity and narrowing the passageway for the bloodstream. This can lead to buildup of fat and cholesterol particles on the wall interiors, leading to even more constriction. The narrowing also makes it more likely that blood clots will get jammed in the passage, with the immediate danger of blood flow cutoff.
Arteriosclerosis can constrict arteries enought so that too little blood is reaching organs and other parts of the body. If blood supply to the heart is lessened or cut off, the result can be a heart attack, while a similar reduction or blockage to the brain can cause a stroke. The extra strain on the heart as it works to pump blood through narrowed arteries can cause thickening and stretching of the heart muscle. A heart can be enlarged to the point where it can no longer pump enough blood. Thus hypertension can lead directly to heart failure.
Blood flow blockage to the kidneys caused by arteriosclerosis is extremely serious, as the kidneys are the body’s disposal units, keeping waste out of the blood. If left untreated, the kidneys begin to fail, and the blood’s waste levels start to rise. Failure makes either dialysis or a kidney transplant necessary to savethe patient’s life. About one quarter of dialysis patients have had their kidneys fail due to high blood pressure.
Hypertension’s causes and symptoms
There are several normal reasons why blood pressure can go up temporarily: increased physical activity is one, reacting to a stress situation is another. Lower the activity level, eliminate the stress, and the blood pressure goes back to normal. This kind of temporary increase is not hypertension. It’s when multiple high readings are found over a span of time that hypertension is diagnosed.
In the vast majority of cases, the cause of hypertension is unknown. 90-95% of hypertensive persons have this unknown-cause type, called “primary” or “essential” hypertension. Hypertension caused by another medical condition, on the other hand, is “secondary” hypertension, and can result from various other ailments. Kidney disorders often bring on secondary high blood pressure because the kidneys are not removing enough extra salt and water from the bloodstream, which increases the overall pressure. Such disorders can include kidney infections, renal kidney stenosis (a localized constriction of the arteries leading to the kidneys), and others.
Other causes of secondary high blood pressure include: Cushing’s syndrome causing tumors of the adrenal and pituitary glands, leading in turn to excessive levels of adrenalin, cortisol, and aldosterone which raise blood pressure; blood vessel diseases; thyroid gland disease; alcoholism; some presription drugs; and pregnancy..
Although it is not known what the direct cause is of most people’s hypertension, it is known that there are factors that will increase the risk of developing the problem.
Some factors are:
- Age over 60 years
- Male gender
- Race (higher incidence among the African American population)
- Heredity
- Sensitivity to salt
- Sedentary habits
- Obesity
- High alcohol consumption
- Oral contraceptives
Of these, obviously some are beyond control, like sex and age and race, or inherited familial tendency to high blood pressure. However, people who have one or more unavoidable risk factors can stay away from the factors that can be controlled, to decrease the likelihood that they’ll become hypertensive.
Diagnosing high blood pressure
Regular periodic checks of blood pressure are important precisely because the condition has no symptoms of its own. The familiar blood pressure cuff, or sphygnomanometer, is wrapped around the upper arm and tightened by inflating it with a small attached pump. The cuff’s pressure briefly cuts off the flow in one of the arm’s arteries, and then the cuff pressure is released while a stethoscope is positioned over the artery so the medical practitioner can listen to the sound of the pulsing blood returning to the artery. The stethoscope first picks up the systolic beat as the heart forces blood through the vessel, and then the diastolic part of pulse cycle as the heart and the artery relax between beats. Both systolic and diastolic pressures are recoreded on the cuff’s mercury gauge.
Temporary rises in blood pressure can come from things like pain, temporary physical and emotional stress, anxiety, etc. Because of this, as noted earlier, a diagnosis of hypertension is not made from a single reading. If the first reading is over 140/90, the physician will take another reading at a later time. A hypertension diagnosis usually results from two or more later high readings, after the first one. Then there’s “white-coat hypertension”, the tendency of many people to have high blood pressure in doctors’ offices. This type of high reading has usually been blamed on situational anxiety, although a study done in Italy in 2001 raised questions about dismissing these results as unrelated to true hypertension.
In elderly persons, it is not uncommon to find systolic hypertension coupled with normal or low diastolic pressure, for instance a reading of 170/70 mm Hg. This systolic hypertension tends to be associated with hardening of the arteries.
These are the blood pressure reading classifications, listed by increasing severity:
- normal blood pressure: lower than 120/80 mm Hg
- high normal: 130–139/85–89 mm Hg
- mild hypertension: 140–159/90–99 mm Hg
- moderate hypertension: 160–179/100–109 mm Hg
- severe hypertension: 180–209/110–119
- very severe hypertension: 210/120 or higher
In order to evaluate a patient for possible hypertension, the typical exam would include:
- Family and medical history
- Physical exam
- Examination of the blood vessels of the eye (opthalmoscopy)
- Electrocardiograph (ECG)
- Chest x-ray
- Blood and urine testing
Taking the patient’s family and medical histories is needed to help alert the physician to other conditions that could be behind the high pressure, or making it worse. Family members with hypertension can mean that a genetic tendency to the condition is present.
During the physical, the doctor may well take multiple pressure readings at different points during the visit, and with the patient in different positions. Heart and blood flow sounds will be checked with a stethoscope, and notes will be made of pulse, height, weight, and reflexes. The doctor will manually feel (palpate) the internal organs to check for enlargement. In addition, he or she will look at the blood vessels in the eyes with an opthalmoscope, to check for hemorrhages or abnormal thickness or narrowing caused by hypertension.
The patient may be checked with an electrocardiagram, to evaluate the heart’s electrical activity, and to see whether the cardiac muscle is abnormally enlarged or damaged due to artery blockage. Enlarged heart muscle and other heart problems, and lung disease may be revealed by a chest X-ray
Testing blood and urine samples are additional ways to check for the possibility of other physical ailments that are known causes of hypertension..
Treating high blood pressure
Primary hypertension – in other words, high blood pressure with no detectable cause – has no cure, but proper treatment can nearly always bring it down to healthier levels. Treatment is undertaken to reduce the pressure to the point where heart disease and other hypertension complications are prevented. With secondary hypertension, caused by other disorders, the causing disease is treated as well as the high blood pressure. If and when the underlying ailment is cured, the secondary hypertension may be too.
The usual techniques for lowering blood pressure include changing the patient’s diet and prescribing a regular exercise routine. If no kidney or heart damage has taken place in a person with mild to moderate hypertension, such changes are often the core of initial treatment.
Some behavioral changes that are capable of bringing blood pressure down by approximately 5-10 mm Hg are:
- Lowering salt intake in the diet
- Lowering dietary fat
- Weight reduction
- Exercising regularly
- Stopping smoking
- Drinking less alcohol
- Stress management
There are also natural alternative methods which may be approved by the patient’s doctor for reducing blood pressure, or even keeping it from developing in the first polace. Aromatherapy is a good example, which can help reduce stress with the use of essential oils. The fragrances can be inhaled from a bottle during periods of tension, and/or the oils can be massaged into the skin before retiring, usually just below the collarbone to release fragrance and promote relaxation. Lavender and blue chamomile are two essences that have shown stress releaving effects.
Another avenue to explore is food therapy, which can have demonstrated benefits for blood pressure. For instance, celery will dilate muscles that regulate blood pressure, and celery juice is mildly diuretic. Sodium and excess fluid in the circulatory system can by lowered by eating fresh vegetables and fruits that are high in magnesium and potassium. The reduction of dietary sodium lowers blood pressure, whether or not hypertension is present, according to a study published in 2001. Garlic has been discovered to have a similar effect. The active ingredient is thought to be allicin, which is present both in enteric-coated garlic capsules and in fresh garlic.
Lowered blood pressure can also be accomplished through relaxation and meditation. Similar techniques also have good effects: focusing on calming music, the use of mental imagery, such as imagining coolness seeping into one’s pores and spreading quietly throughout the body, bringing blood pressure to normal levels. Yoga specialists recommend two poses, the corpse pose and the knee squeeze pose, that are especially good for tension relief and healthy blood flow when combined with breathing exercises.