What is Blood Pressure?

Blood pressure is the force created by the heart as it pushes blood into the arteries and the circulatory system. When the heart pumps, it causes blood to flow through the arteries and into the arterioles.  As the blood goes through the arterioles, the arterioles either contract or expand altering both the amount of blood flow and the resistance to blood flow. If the arterioles remain in a contracted form, they create high blood pressure.  The heart must then pump harder because the arterioles are exerting a greater resistance to blood flow.  

High blood pressure is often called the "silent killer". It is called this because there are usually no symptoms. Very high blood pressure can also cause arteries to bulge (aneurysm) or burst (hemorrhage).

Blood Pressure and Heart Disease

High blood pressure is a risk for both heart disease and stroke.  Unfortunately, high blood pressure usually has no specific symptoms and no early warning signs. It directly increases the risk of heart disease.  High blood pressure is a risk for heart disease because the heart is working harder than normal thus putting the heart and the arteries under a greater strain.  When the heart is forced to work harder for long periods of time, the heart becomes enlarged.  A heart that is slightly enlarged may function okay but a severely enlarged heart has a hard time pumping a sufficient amount of blood.  Given this, blood pressure is also a risk for strokes.  

It is estimated that over 60 million Americans have high blood pressure.  Of this 60 million, about 35 percent don't know they have it.

Blood pressure and Kidney disease

High blood pressure and kidney disease are closely related. High blood pressure is a common cause of kidney failure in Australia. One mechanism for this is the production of a hormone called 'renin' by the kidneys. If the kidneys aren't functioning properly, renin can be produced inappropriately, raising the blood pressure.

If high blood pressure is left unchecked, it can cause blood vessels in the kidneys to become thickened and narrowed, possibly leading to reduced blood supply and reduced kidney function.