Blood pressure is the force of blood against the walls of your arteries as the heart pumps blood. If this pressure rises and stays high over time, it can damage the body in many ways. High blood pressure increases your chance of heart disease, stroke and kidney failure and is dangerous because it often has no symptoms. It is referred to as the "silent killer."
It is important to know your blood pressure numbers, even if you are feeling fine. If your blood pressure is too high, treatment may help prevent damage to your body's organs.
For more information see High Blood Pressure: A Look at the Causes - National Kidney Foundation.