When does diastolic blood pressure occur during the cardiac cycle?

Diastolic blood pressure refers to the pressure within the arteries when the heart is in a state of relaxation and filling with blood, which occurs during the diastolic phase of the cardiac cycle. During this phase, the heart's ventricles are not contracting, allowing blood to flow from the atria into the ventricles. As the heart fills with blood, the pressure in the arteries decreases to its lowest point, which is measured as diastolic blood pressure.

The importance of this phase lies in maintaining sufficient blood flow and pressure to the organs and tissues while the heart prepares for its next contraction. Understanding this helps to appreciate how blood pressure readings are taken: systolic pressure is measured during the heart's contraction phase, whereas diastolic pressure reveals the status of the heart and vascular system when it is at rest.