Diastolic blood pressure is defined as the minimum pressure recorded during the cardiac cycle. It is recorded during diastole. Therefore, it is called diastolic pressure. It indicates the load against which heart has to work.
Diastolic blood pressure is the bottom reading. After the heart empties the blood from the ventricle, the aortic valve shuts to prevent blood from returning into the heart from the rest of body. The heart muscles then relax and the ventricle expands as blood fills it up from the left atrium, which has received it from the lungs.
Within the arteries, the blood pressure rapidly falls until it reaches its lowest point. The diastolic blood pressure reflects this lowest point of blood pressure. During this time the ventricles relax between contraction. Before pressure falls further, the ventricle contracts again and the blood pressure starts to rise back up to the systolic level.
As arteriosclerosis sets in there is a relative drop in diastolic blood pressure due to reduced arterial compliance.
Diastolic blood pressure
