Globally, the World Health Organization (WHO) estimated that about 26% of the world population have hypertension and it is accounted for 6% of death per year. With just a rough analysis on this set of statistic, it is enough for us to draw a conclusion that, hypertensive disorder is rather common and has a great impact on our community and our lives, directly or indirectly so.
What is hypertension? The fact is, because the normal blood pressure among individuals in any given population varies so greatly that clinicians do not recommend giving an exact word by word or a concrete numerical value definition to it, as to avoid confusion. In Layman's term however, hypertension is a diagnosis given by a doctor to a patient with long term increase of blood pressure. Medical schools all across the world chose a value of blood pressure above which the risk of complications such as heart attack developing is greatly increased. Most renounced medical textbooks suggested that, a person is considered hypertensive when his or her average systolic blood pressure throughout the day is more than 140 mm Hg, diastolic blood pressure more than 90 mm Hg, patient has at least one symptom such as headache and that he or she is managed under anti-hypertensive drugs.
What causes hypertension? There are many conditions that can send blood pressure shooting up. Events such as emotional changes, exercises, temperatures and pregnancies increase blood pressure temporarily, to increase blood circulation as needed by the body, these are normal adaptive process of human body, or scientific term for it 'physiological'. But when blood pressure is constantly alleviated, it brings harm rather than good, it damages organs like eyes, heart, brain and kidneys. First of all, constant increase of blood pressure can be a sign of other diseases that a person has, this is called 'secondary hypertension' examples are kidney (renal) diseases, cancers, various hormonal (endocrine) disturbances and intake of steroid drugs. Secondary hypertensions are merely 5% of all hypertensive cases, what about the other of 95%? In 95% of cases, the exact cause of hypertension is not well understood and so the high blood pressure condition is identified as the primary disease in itself, so called 'essential hypertension'. Despite of not having an exact cause, there are few risk factors however that are suspected to contribute to the development of essential hypertension. Among others, weight gains, high dietary salt intake, diabetes, alcohol consumptions, psychosocial stress, lack of exercises and positive family history (presence of hypertensive patients in a family).
Who can get essential hypertension? In short, everyone! But prevalence is significantly higher in certain race, geographic area, age group and gender. Risk is higher for people who live in urban areas, cases of hypertension are higher among African ethnicity compared to Caucasian ethnicity, with lowest among Hispanic ethnicity. Middle age males, elderly population, citizen of industrialized nations, post-menopausal women, white collars and people with above mentioned risk factors are more prone to essential hypertension. Essential hypertension is rarely diagnosed in children and teenagers.
How does hypertension develop? The mechanics of blood pressure fluctuation in the body is determined by three factors. First the heart, the stronger the heart contracts and the higher the heart rate is, the more blood is being pumped into the circulation, thus increases the blood volume in the vessels. Second the state of the blood vessels throughout the body, blood vessels especially arteries are not simply rigid network of pipes that commute blood, but rather their size and diameter changes. Logically when the size and diameter of the arteries decreases, the higher the resistance is to the blood flow, the correct term for it is, 'increased peripheral resistance', when it occurs, the pressure inevitably increases. Third the blood volume, since the circulation of the body is a closed system, any addition or subtraction of fluid will change the pressure load. Normal circulating blood volume of an adult is 3.5 - 4 liters; the range is actively regulated by the kidneys. Hypertension occurs as a total effect of all three factors.
In conclusion, hypertension is a common disorder, well studied but yet to be well understood. It is not an equal opportunity disorder, but nevertheless everyone is at risk of getting it.
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