Which statement is true about diastolic blood pressure?

• A. It measures pressure during contraction
• B. It measures pressure during relaxation
• C. It is the average of systolic and diastolic
• D. It is not clinically relevant in adults

Answer: (B)

Diastolic blood pressure is the arterial pressure when the heart is at rest between beats. This relaxation phase (diastole) is when the ventricles fill with blood, so the arterial walls experience their lowest pressure. That’s why the statement that diastolic pressure measures pressure during relaxation is the best description. The pressure during contraction is systolic pressure, not diastolic. It’s not simply the average of systolic and diastolic; mean arterial pressure is more accurately diastolic pressure plus about one-third of the pulse pressure. Clinically, diastolic pressure in adults is important for assessing cardiovascular risk and guiding hypertension treatment.