About one in three adults in the U.S. have high blood pressure. More than 90% of adults who survive into their 80s will develop elevated blood pressure -- also called hypertension -- and about 50% of people will have it by age 60.
High blood pressure usually has no symptoms, even if it is severely elevated. Only 35% of people with high blood pressure have it under control. If you're one of the millions of people with uncontrolled hypertension, your arteries may be paying the price.
High Blood Pressure Basics
Blood pressure is the pressure inside the arteries. It's reported in two numbers; for example, "125 over 80." What do these numbers mean?
The top number is the systolicblood pressure. This is the peak pressure, when the heart pumps and expands the arteries.
The bottom number is the diastolicblood pressure. When the heart relaxes, the pressure in the arteries falls to this value.
Normal blood pressure is less than 120 over 80. Treatment is recommended for blood pressure above 140 over 90 for most people. Treatment may be considered at lower levels, depending on other medical conditions you may have.
How High Blood Pressure Causes Atherosclerosis
When the heart beats, it pushes blood through the arteries in your entire body. Higher blood pressures mean that with each beat, arteries throughout the body swell and stretch more than they would normally. This stretching can injure the endothelium, the delicate lining of all arteries, causing arteries to become stiffer over time.
Healthy endothelium actively works to prevent atherosclerosis -- also called hardening of the arteries -- from developing. Injured endothelium, on the other hand, allows more "bad" LDL cholesterol and white blood cells to enter the lining of the artery. The cholesterol and cells build up in the artery wall, eventually forming the plaque of atherosclerosis.
Plaque is dangerous. Although it often grows without symptoms for years, plaque can suddenly rupture, forming a blood clot that blocks the artery, which keeps oxygen from getting to the heart muscle or the brain. The result can be a heart attack or stroke.