What is the systolic blood pressure measurement?

• A. The pressure in the arteries when the heart ventricles contract
• B. The pressure in the arteries when the heart ventricles relax between beats
• C. The pressure in the veins during ventricular contraction
• D. The pressure in the heart chambers when the ventricles fill

Answer: (A)

Systolic blood pressure is the pressure in the arteries during the heart’s contraction, when the ventricles push blood out into the arterial system. This is the peak pressure reached as the heart squeezes blood, and it’s the top number you see in a blood pressure reading. The heart spends less time in this state, but it’s when the arterial pressure is highest.

If the heart is relaxing between beats, the arterial pressure drops to the diastolic level—that’s the pressure measured when the ventricles are filling and relaxing. The other options describe pressures that aren’t arterial systolic pressure: the arteries’ pressure during relaxation is diastolic, the veins’ pressure during ventricular contraction isn’t the systolic arterial pressure, and the pressure inside the heart chambers during filling refers to filling phase (end-diastolic) rather than the peak arterial pressure during contraction.