Hypertension, or high blood pressure, is characterized by increased resistance to blood flow throughout the body. According to the American Heart Association, or AHA, about 74.5 million Americans over the age of 20 have hypertension, and the cause of 90 to 95 percent of hypertension cases is unknown. Although it has few symptoms, hypertension is characterized by numerous cardiovascular changes that can affect a person's health and lead to more serious health conditions.
Insulin Resistance
Insulin resistance—a reduced sensitivity to the action of insulin—may be a characteristic of hypertension. According to a 2004 study by Mohammed F. Saad and colleagues published in the journal "Hypertension," insulin resistance, but not insulinemia, or abnormally high levels of insulin in the blood, was associated with hypertension and blood pressure in non-diabetic subjects, although ethnic differences in the degree of insulin resistance appear to exist. The researchers note that neither insulin resistance or insulinemia was associated with hypertension or blood pressure in people with type 2 diabetes in Caucasians, Hispanics and African Americans. Because hypertension is characterized by insulin resistance and altered glucose tolerance, elevated plasma concentrations of insulin produce unfavorable effects on the walls of blood vessels, and may also adversely affect a person's lipid profile.
Enlarged Left Ventricle
An enlarged left ventricle—the heart chamber responsible for pumping blood to the body's tissues—is a characteristic of hypertension. According to MayoClinic.com, elevated blood pressure forces the heart to work harder than usual to pump blood to the rest of the body. The extra force required to push blood through narrowed vessels or vessels with significant resistance causes the heart's left ventricle to enlarge or stiffen, a condition called left ventricular hypertrophy. Left ventricular hypertrophy is, in some ways, similar to the effects of resistance training on the body's skeletal muscles: the more resistance applied to the skeletal muscles, the more they grow, or hypertrophy. The hypertension-induced left ventricular hypertrophy limits the ventricle's pumping ability and predisposes a person to myriad cardiovascular problems, including heart attack, heart failure and sudden cardiac death.
Decreased Arterial Compliance
Decreased arterial compliance, or alterations in the blood vessels' structure and function, is a characteristic of hypertension. According to MedlinePlus, blood vessel damage, including arteriosclerosis, is a common complication of chronically elevated blood pressure. MayoClinic.com states that healthy arteries are strong, flexible and elastic, and that their inner walls are smooth to allow blood, along with nutrients and oxygen, to flow freely to the organs and tissues. However, over time, elevated blood pressure can damage the cells lining the arteries' inner walls, which causes a series of events that result in arterial wall thickening and stiffening. Decreased arterial compliance is called arteriosclerosis, or hardening of the arteries.
