What is High Blood Pressure?

Updated:Aug 26,2016

About High Blood Pressure. What's so important about blood pressure?

High blood pressure, also known as HBP or hypertension, is a widely misunderstood medical condition. Some people think that those with hypertension are tense, nervous or hyperactive, but hypertension has nothing to do with personality traits. The truth is, you can be a calm, relaxed person and still have HBP.

Untreated high blood pressure damages and scars your arteries.

Let's look at the facts about blood pressure so you can better understand how your body works and why it is smart to start protecting yourself now, no matter what your blood pressure numbers are.

By keeping your blood pressure in the healthy range, you are:

  • Reducing your risk of the walls of your blood vessels walls becoming overstretched and injured
  • Reducing your risk of having a heart attack or stroke; and of developing heart failure, kidney failure and peripheral vascular disease.
  • Protecting your entire body so that your tissue receives regular supplies of blood that is rich in the oxygen it needs

What happens in the body when blood pressure is high?

View an animation of high blood pressure.Blood pressure measures the force pushing outwards on your arterial walls.

The organs in your body need oxygen to survive. Oxygen is carried through the body by the blood. When the heart beats, it creates pressure that pushes blood through a network of tube-shaped arteries and veins, also known as blood vessels and capillaries. The pressure --- blood pressure --- is the result of two forces. The first force occurs as blood pumps out of the heart and into the arteries that are part of the circulatory system. The second force is created as the heart rests between heart beats. (These two forces are each represented by numbers in a blood pressure reading.)

View an animation of high blood pressure.

The problems from too much force.

Healthy arteries are made of muscle and a semi-flexible tissue that stretches like elastic when the heart pumps blood through them. The more forcefully that blood pumps, the more the arteries stretch to allow blood to easily flow. Over time, if the force of the blood flow is often high, the tissue that makes up the walls of arteries gets stretched beyond its healthy limit and damaged. This creates problems in several ways.

  • Vascular weaknesses
    First, the overstretching creates weak places in the blood vessels, making them more prone to rupture. Problems such as hemorrhagic strokes and aneurysms are caused by ruptures in the blood vessels.
  • Vascular scarring
    Second, the overstretching can cause tiny tears in the blood vessels that leave scar tissue on the walls of arteries and veins. These tears and the scar tissue are like nets, and can catch debris such as cholesterol or blood cells traveling in the bloodstream.
  • Increased risk of blood clots
    Trapped blood can form clots that can narrow (and sometimes block) the arteries. These clots sometimes break off and block vessels and the blood supply to different parts of the body. When this happens, heart attacks or strokes are often the result.
  • Increased plaque build-up
    The same principle applies to our blood flow. Cholesterol and plaque build-up at the damaged sites in the arteries and cause the blood flow to become limited or even cut off altogether. As this happens, pressure is increased on the rest of the system, forcing the heart to work harder to deliver blood to your body. Additionally, if pieces of plaque break off and travel to other parts of the body, or if the build-up completely blocks the vessel, then heart attacks and strokes occur.
  • Tissue and organ damage from narrowed and blocked arteries
    Ultimately, the arteries on the other side of the blockage do not receive enough freshly oxygenated blood, which results in tissue damage.
  • Increased workload on the circulatory system
    Think of it this way: In a home where several faucets are open and running, the water pressure flowing out of any one faucet is lower. But when pipes get clogged and therefore narrow, the pressure is much greater behind the clog. And if all the household water is flowing through only one faucet, the pressure is higher still.

When the arteries are not as elastic because of the build-up of cholesterol or plaque or because of scarring, the heart pumps harder to get blood into the arteries. Over time, this increased work can result in damage to the heart itself. The muscles and valves in the heart can become damaged and heart failure can result.

Damage to the vessels that supply blood to your kidneys and brain may negatively affect these organs.

You may not feel that anything is wrong, but high blood pressure can permanently damage your heart, brain, eyes and kidneys before you feel anything. High blood pressure can often lead to heart attack and heart failure, stroke, kidney failure, and other health consequences.

Take the time to learn about what the numbers in your blood pressure reading mean.

Watch as Dr. Donna Arnett of the American Heart Association explains what high blood pressure is and how to prevent it from occurring

This content was last reviewed on 08/04/2014.

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