Transient elevations in systolic blood pressure occur as normal adaptations during fever, physical exertion, and emotional upset, such as during anger and fear. Persistent hypertension, or high blood pressure, is common in obese people because the total length of their blood vessels is relatively greater than that in thinner individuals.
Although hypertension is usually asymptomatic for the first 10 to 20 years, it slowly but surely strains the heart and damages the arteries. For this reason, hypertension is often called the “silent killer”. Prolonged hypertension accelerates arteriosclerosis and is the major cause of heart failure, vascular disease, renal failure, and stroke. Because the heart is forced to pump against greater resistance, it must work harder, and in time the myocardium enlarges. When finally strained beyond its capacity to respond, the heart weakens and its walls become flabby. Advanced warning signs include headache, sweating, rapid pulse, shortness of breath, dizziness, and vision disturbances.
Hypertension also ravages blood vessels, causing small tears in the endothelium and increasing the demand for energy in countering the excessive mechanical load on the arterial vessels – this accelerates the progress of atherosclerosis. Furthermore, a stretched muscle cell accumulates more lipid than a relaxed muscle, further enhancing this metabolic and morphological change in cells and tissues. As the vessels become increasingly blocked, blood flow to the tissues becomes inadequate, and vascular complications begin to appear in vessels of the brain, heart, kidneys, and retinas of the eyes.
Systolic or pumping pressure, the higher of the two is normally around 120 in a healthy adult and the lower diastolic about 70, normally expressed as 120/70. 130/80 is average for a 40 yr old NZ male, 117/75 for a 40 yr old female. Hypertension is defined physiologically as a condition of sustained Glucofort elevated arterial pressure of 140/90 or higher (which is dangerously high), and the higher the blood pressure, the greater the risk for serious cardiovascular problems. As a rule, elevated diastolic pressures are more significant medically, because they always indicate progressive occlusion and/or hardening of the arterial tree.
About 90% of hypertensive people have primary, or essential, hypertension, in which no underlying cause has been identified by their doctor. The following factors are believed to be involved:
1. Diet. Dietary factors that contribute to hypertension include excessive use of table salt, saturated fat, and cholesterol intake and deficiencies in certain metal ions (Potassium, Calcium and Magnesium).
3. Age. Clinical signs of the disease usually appear after age 40.
4. Race. More blacks than whites are hypertensive, and the course of the disease also varies in different population groups.
5. Heredity. Hypertension runs in families. Children of hypertensive parents are twice as likely to develop hypertension as are children of normotensive parents.