What is diastolic blood pressure?

• A. The highest pressure of the artery during the heart's contraction.
• B. The lowest pressure of the artery when the vessels are relaxed.
• C. The average pressure in the arteries during the day.
• D. The pressure in the veins during diastole.

Answer: (B)

Diastolic blood pressure is the pressure in the arteries when the heart is at rest between beats. During diastole the ventricles relax and fill with blood, so arterial pressure drops to its lowest point in the heart’s cycle. Blood pressure readings have two numbers: the higher is systolic pressure (peak during contraction), and the lower is diastolic pressure (baseline when the heart is relaxed). The other options describe the peak pressure during contraction, an average over the day, or pressure in the veins, which are not what this term refers to.