High Blood Pressure-What Happens Healthy arteries have smooth inner walls. Your blood flows through them without a problem. The blood vessels stay strong and flexible.

But when you have high blood pressure, blood flows through your arteries with too much force, even though you can't feel it. Over time, this pressure damages the walls of your arteries. They aren't smooth anymore. They get rough spots on them where fat and calcium start to build up. This buildup is called plaque (say "plak").

Plaque is part of atherosclerosis, sometimes called "hardening of the arteries." Over time, the plaque narrows the artery and blocks blood flow through it.

Atherosclerosis makes your arteries narrower. It also makes them stiffer. Blood can't flow through them as easily. This lack of good blood flow starts to damage some of the organs in your body.

This damage doesn't happen all at once. It happens slowly over time. But you can't tell that it's happening, because you don't feel anything. It can lead to:

• Coronary artery disease and heart attack.
• Heart failure.
• Stroke.
• Kidney failure.
• Peripheral arterial disease.
• Eye damage (retinopathy) that can lead to vision loss and blindness.

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