What is hypertension?
Hypertension is a disorder of circulation in which elevated blood pressure results in increased tension in the walls of the blood vessels. Since it is impossible to routinely measure blood vessel wall tension, hypertension is assessed indirectly by measuring blood pressure. Thus, high blood pressure and hypertension are used to describe the same condition. Almost one in three adults in the United States and Australia and one in five Canadian adults five Americans have high blood pressure. In addition, there is higher incidence in African-American adults then Caucasian or Hispanic-American adults. However, no one is safe.
Despite such high occurrence, many people (perhaps 30%) high blood pressure don‘t even realize their blood pressure is elevated. This is because they have not really experienced significant symptoms or have not had a physical examination in a long time. This is why high blood pressure is often referred to as the “silent killer”.
How is high blood pressure diagnosed?
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Typically, a resting blood pressure greater than 140/90 (read as “140 over 90”) is regarded as high blood pressure or hypertension. Here, 140 is the systolic blood pressure (measured in millimeters of mercury) or the pressure in large arteries when the heart contracts. In contrast, the 90 refers to diastolic blood pressure or the pressure in large arteries when the heart relaxes. Many physicians consider blood pressure measures under 120/80 to be healthier. That means that a systolic of 120 or higher but below 140 and a diastolic of 80 or higher but below 90 mmHg is considered borderline high blood pressure. |
Why is hypertension deleterious?
Chronic hypertension is a medical problem for at least two reasons. First, if the pressure in the arteries is elevated, as occurs in hypertension, the heart has to work harder to generate more pressure to keep the blood flowing. This extra work causes the heart muscle to become overworked and become enlarged (hypertrophy). Over time an enlarging heart from high blood pressure can become dysfunction and eventually fail. The second complication associated with chronic hypertension is that the elevated pressure can traumatize blood vessel walls, which leaves them more susceptible to atherosclerotic development, as explained previously. Hypertension can result in other medical complications such as damage to nephrons, the tiny blood processing units of the kidneys.
What factors are associated with hypertension?
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Obesity is associated with the development of hypertension. In many obese people, reductions in blood pressure go hand in hand with reductions in body fat. In addition, if exercise is incorporated into the weight-reduction program, blood pressure is reduced beyond that which can be accounted for by weight loss alone. Stress reduction has also been shown to lower elevated blood pressure significantly. Also, individual diet components such as high fat and high saturated fat foods as well as high sodium foods have been associated with the development of hypertension. |
The relationship between diets high in sodium and hypertension does not seem to exist in everyone and will be realized in only about 10 percent of people with high blood pressure. These people are sometimes labeled “salt sensitive”. This means that their blood pressure can be reduced by following a low-sodium diet (Less than two grams of sodium daily). Finally, smoking and/or chronic and excessive alcohol consumption is also associated with hypertension.
