What Causes High Blood Pressure
Hypertension or high blood pressure occurs when normal blood pressure readings are too high, that is above 120/80mmHg (millimeters of mercury). The top number represents the systolic pressure (pressure created when the heart beats) whilst the bottom number is the diastolic pressure (pressure inside the blood vessels when the heart is resting). A blood pressure reading of 140/90 or higher is considered high, either numbers or both are too high.
There is also pre-hypertension when the readings are 120-139 for the systolic blood pressure and, 80 to 89 for the diastolic blood pressure. Any of these readings or combinations could indicate the development of hypertension.
The force of the blood pumped by the heart is what is used to measure blood pressure; there are factors that will affect the blood pressure levels. These are: salt intake, water in the body, the condition of the kidneys, nervous system and blood vessels, and body hormone levels. There are cases where the exact cause of high blood pressure cannot be identified due to multiple factors (essential hypertension). These cases are more common in what is called secondary hypertension created by specific conditions (diabetes, obesity etc), habits (such as alcohol or drug abuse) or medications such as appetite suppressants and migraine medications.
Causes of High Blood Pressure
Genetic Factors
Genes are a significant contributor to high blood pressure. Family history of hypertension increases its risk, especially in African American families. Persons that are younger in age are more likely to develop high blood pressure if their DNA suffers from severe mutations or deletions of its portions within the gene for a protein. Less severe mutations in the genetic code will take a much longer time to develop into a disorder however, after a period of time they will eventually lead to hypertension as the body’s feedback system is weakened.
Disease of the Kidneys
Renal hypertension occurs when the renal artery that supplies blood to the kidney experiences narrowing (atherosclerotic or fribromuscular hyperplasia), this narrowing damages the blood flow to the affected kidney which is then stimulated to produce renin and angiotensin. Renin and angiotensin are hormones that when coupled with aldosterone (hormone that balances salt and water in the body) narrows the peripheral arteries in the body and cause high blood pressure.
Adrenal Gland Tumors
The adrenal glands are located on top of the kidneys; there are two types of tumors which affect these glands, one causes an excess amount of aldosterone while the other produces a surplus of catecholamines. The two tumors will produce high levels of adrenal hormones which can cause high blood pressure.
Coarctation of Aorta
The aorta is the major artery that leads out from the heart. The narrowing of this artery usually takes place above the renal arteries; which is referred to as coarctation and restricts the blood flow. The aorta’s function is to transport blood from the heart to the vessels that provide blood and nutrients throughout the body. This condition is a common factor of hypertension in children. The restriction of blood to the kidney results in hypertension as described earlier.
