Hypertension is the medical term used to describe the physical condition of high blood pressure. Approximately 50 million people in the United States are afflicted with hypertension, with similar proportions of the populations of other Western countries also at risk. High blood pressure is more commonly found in older adults (defined as persons over the age of 50); persons of African descent in these countries are more seriously affected, due to genetic reasons.

Hypertension is a multidimensional health problem that occurs when the pressure created within the arteries by the usual functioning of the cardiovascular system places excess pressure on the arteries. The causes of high blood pressure are varied. The cardiovascular system delivers blood and its cargos of energy fuels, oxygen, and nutrients through the power of the heart. Each heartbeat creates pressure along the entire arterial system. The flow of blood and the function of all related systems will be optimal at a range of blood pressures. Blood pressure that is too high for the arterial vessels, or less commonly, blood pressure that is too low, create malfunctions within the entire cardiovascular network.

There is often more than one discrete cause of hypertension in any person. Typically, a number of circumstances exist to create the basis for the condition, which can include: genetic structure (there is a significantly greater likelihood of high blood pressure if one or both parents of a person had hypertension; lifestyle factors (eating habits, excess weight, level of physical fitness, particularly the level of aerobic fitness, excessive alcohol consumption, and smoking; one or more of these circumstances will increase the risk of the person developing high blood pressure); medications (certain medications that will contribute to high blood pressure include decongestant nasal sprays and various anti-inflammatory medicines); kidney and various hormonal (endocrine system) disorders.

Hypertension presents difficulties in its detection because it provides few outward physical symptoms. Instead, high blood pressure is the connection to a series of potential fatal events, including stroke, heart attack, heart arrhythmia (irregular heart beat), and kidney failure. The only determinative investigation for the existence of hypertension is the blood pressure test. Using a device attached to the person's arm, at heart level, the pressure generated by the cardiovascular system is measured using two indicators. As the heart beats, the power of blood being

Hypertension-related vascular effects primarily involve diminution in diameter of the retinal vessels.
pushed along the artery by this pulse creates pressure on the arterial wall. The peak level of this type of blood pressure at each beat is known as the systolic pressure. During the rest interval between each heartbeat, the measure of resistance within the small arteries of the cardiovascular system to the flow of blood is determined. This pressure is referred to as the diastolic pressure.

Blood pressure is a variable within all persons; factors such as recent physical exercise, the consumption of a stimulant such as caffeine, emotional state, and medication may all significantly influence the outcome of a blood pressure test. For this reason, blood pressures are often measured a number of times before any definitive conclusion will be reached regarding the likely existence of hypertension. A reading of 120/80 (the figures are as calculated from the blood pressure test equipment scale, measured in mm of mercury, or mmHg) is accepted as a healthy blood pressure standard. When the systolic reading exceeds 140, or when the diastolic measure is greater than 90, or when both indicators are above these limits, the probability of the presence of hypertension is very high.

While hypertension may be difficult to lower significantly, it can be managed effectively through a number of means. Physical fitness and accompanying weight management, with their resulting improved cardiovascular health, are essential components to any treatment of hypertension. Increased weight places stress on the heart and cardiovascular system; the foods typically consumed by adults who are overweight are those high in fat, a substance that tends to lead to the creation of plaque, an artery-clogging substance. When arteries are clogged in this way, the passage through which blood passes becomes smaller, resulting in a correspondingly greater volume of blood being directed against a smaller vessel, increasing pressure on the artery. Physical activity tends to stimulate the production compounds known as high density lipoproteins (HDLs), which have a plaque-resistant effect within the arteries.

Prescription diuretics are sometimes administered to stimulate urine production, with a corresponding reduction in fluid and blood volumes, which tends to ease pressure within the arteries. Other medications, including angiotesin and

Bob Irving experienced hyponatremia while competing in the 1998 Desert Sun Half Ironman in Grand Junction, Colorado.
vasodilators, are prescribed to assist in the constriction and the relaxation of the walls of the arteries.

SEE ALSO Cardiovascular system; Diet; Genetics; Weight gain.