Diastolic Blood Pressure
When The Heart Rests

What is Diastolic? It is indicated by the lower or smaller of the 2 numbers on your blood pressure monitor display when you take your blood pressure. The larger or top number indicates the Systolic.

Some people are under the illusion that the heart never rests, but it actually does if only briefly between beats. When it does your blood pressure in your arteries is at it`s lowest. Your blood pressure monitor measures the pressure at this time as the second number after the dash. E.g. 120/80.


What is happening in your heart during Diastole?

Your heart has 4 main chambers, two on the left and two on the right. The top chambers are called the right and left atrium, and the bottom chambers are called the right and left ventricles.

During Diastole the blood fills up in the top atrium chambers, while the two bottom chambers rest. The valves won`t open until the pressure is higher in the atria than the ventricles.

You may be interested to know that the word “diastole” came from a Greek word meaning “a drawing apart” and this is descriptive of what the ventricle chambers do next. They relax, expand, and as the mitral valve and the tricuspid valves open they fill with blood from the atria ready for the next contraction that will follow quickly after.

In a normal healthy heart this process is done effortless by the heart muscle, but if the muscles (seen as the thick orange areas at the bottom of the heart in the diagram) of the ventricles have become thickened with over work or stiffened by lack of elasticity, these chambers cannot relax and open wide enough to let in the needed blood volume to be pumped around the body. This is called Diastolic Heart Failure.

In some people the DBP is raised but not the SBP. This is called Isolated Diastolic Hypertension (IDH) and usually happens as a person ages. It is not viewed as serious as High Systolic Hypertension but never-the-less, a patient can go on to develop such. Doctors therefore will keep a close monitor on those patients.

The blood pressure reading of a person with IDH would show the lower number as being above 80 while the top number indicated normal 120. Something like 120/110.