Hypertension is the leading cause of stroke, kidney and heart disease. According to the Centers for Disease Control and Prevention, it affects roughly 74.5 million people in the U.S. alone and contributed to the deaths of 326,000 Americans in 2006. Because this condition has such serious consequences, it is important to closely examine the biological effects of hypertension on the human organism.
Vascular Weakness
Blood pressure refers to the force inside arteries pushing out against the arterial wall. The arteries weaken over time when this pressure is too high.
As the arteries weaken, they no longer resemble flexible tubing. High pressure areas may start to balloon out when they weaken, much the same way a bicycle inner tube bulges when it develops a weak spot. These weakened pockets are called aneurysms. Just as the bicycle inner tube can blow out, the weakened pockets of artery can rupture, causing an internal hemorrhage.
Vascular Scarring
Hypertension can also cause tiny micro-tears in the arterial wall. Scarring results when these tears heal. A scarred artery is no longer smooth. Just as a sanded surface is better able to hold paint, the scarred artery starts holding onto plaques, cholesterol, small clots and other debris.
The accumulation of this material causes the artery to narrow. This creates a vicious cycle because as the artery narrows, blood pressures go up. The heart has to work even harder to circulate the same volume of blood.
In some instances, bits of the debris can break off the arterial wall and circulate downsteam until they block another smaller blood vessel. A stroke or heart attack can result.
Heart Damage
Heart muscles have to work harder to force blood through narrowed arteries. According to the American Heart Association, "the muscles and valves in the heart can become damaged and heart failure can result." This is a chronic condition as the heart muscle becomes progressively less able to circulate oxygenated blood to the organs that need it. When this occurs, the heart enlarges. Shortness of breath, fatigue and edema result. This is also called congestive heart failure.
Kidney damage
Since the filtering units in the kidneys are no more than tiny capillaries, they are exquisitely sensitive to hypertension. High blood pressure causes the capillaries to burst, causing scarring of the kidney. The 2007 Annual Data Report of the U.S. Renal Data System points out that more than 25,000 cases of kidney failure are caused by hypertension alone, making it the second leading cause of end stage kidney disease.
