August 2014

High Blood Pressure and the Risk of Heart Disease and Stroke


High Blood Pressure and the
 Risk of Heart Disease and Stroke


The medical term for high blood pressure is hypertension. High blood pressure is an important risk factor in coronary artery disease and stroke. There are many causes of high blood pressure. There are many treatments for high blood pressure, unfortunately most of these do not actually cure the problems that caused the high blood pressure. In fact, the same is true about atherosclerosis and coronary artery disease as well.


Normal Blood Pressure

When we talk about normal blood pressure there are actually two different things that we measure. The first is the Systolic pressure this is the pressure of blood being forced out of the heart when the heart beats. The second is the Diastolic pressure, this is the pressure in the blood vessels when the heart is in a resting state, between heart beats. Generally, what is commonly considered to be "normal blood pressure" is considered as a range which has been arbitrarily decided upon many years ago.

The normal range for systolic blood pressure is 100 - 139 millimeters of Mercury (or mm Hg) .

The normal range for diastolic blood pressure is 60- 89 mm Hg.


Abnormal Blood Pressure

When the systolic blood pressure is below 100 mm Hg or the diastolic is below 60 mm Hg the individual is said to have low blood pressure. When an individuals systolic blood pressure is greater than 140 mm Hg or diastolic greater than 90 the individual is said to have high blood pressure or hypertension.

When ever you blood pressure is taken the specific numbers obtained are written down in several ways. For example:

120 or as 120/80 both are acceptable ways of designating blood pressure.   

Please note that mm Hg are left out in the two examples above. As a rule they are not added except in scientific documents or when the information is going to a source that would not know they are implicitly present.

Above we suggested that high blood pressure exists when either the systolic pressure rises above 140 mm Hg or the diastolic rises above 90 mm Hg (140/90). In severe hypertension systolic pressure can be as high as 220 mm Hg, or higher. The diastolic blood pressure can rise as high as 140 mm Hg but these values are quite severe and often can lead to a heart attack or stroke if not returned to normal.

In another section we will discuss the other important information about high blood pressure including, causes, diagnosis, and treatments of high blood pressure, in this section all we need to know is that it exists and that it is a key factor in the cause and course of atherosclerosis and coronary artery disease.

In the section on atherosclerosis we discussed structure of the arteries and veins and what atherosclerosis does to them, high blood pressure accelerates this damage. It can cause the artery walls to become hard and thickened causing a condition called arteriosclerosis. These injuries speed up the deposition of cholesterol plaque (atherosclerosis). As this happens, important arteries in both the heart and brain become narrowed increasing the risk of heart attack and stroke.

As these vessels become narrowed there is decreased blood flow to vital organs throughout the body as well as to the heart and the brain. The kidneys may be affected causing them to fail and creating a build up of toxic materials in the body.

Not only does that atherosclerosis cause narrowing of these vessels but the high blood pressure often leads to spasm in these arteries as well. Spasm further narrows the vessels and increases the risk of a blood clot and thromboembolism occurring. As these vessels narrow the heart must work harder to push blood through them, hence it must beat more forcefully, work harder and increase the blood pressure thus creating a vicious cycle.

As the heart is forced to work harder, it may begin to enlarge, a condition called cardiac hypertrophy (See Diagrams: 1 and 2). Eventually, if it works too hard, it may begin to fail. This is referred to as Congestive Heart Failure.




Diagram: 1



Diagram: 2

What Are My Risks of Suffering From Heart Attack or Stroke?