When can diastolic pressure be measured?

Whenever you want: Diastolic blood pressure refers to the pressure in the arteries during the period of heart's relaxation, i.e. Once it finished ejecting blood during contraction. For every single heart beat, there is the period of contraction ("systolic blood pressure") and the relaxation ("diastolic"). In any single cardiac cycle, each of these arterial pressures can be measured.

Regular : The regular blood pressure machine will measure the diastolic pressure. The lower number on the reading represents it.