What does the systolic component of a blood pressure reading measure?

• A. Pressure in the arteries during heart contraction
• B. Pressure in the arteries during heart relaxation
• C. Mean arterial pressure over time
• D. Pressure in the veins

Answer: (A)

Systolic blood pressure reflects the peak pressure in the arteries when the heart contracts and ejects blood into the aorta. This phase, ventricular systole, raises arterial pressure to its highest level, which is what the systolic reading captures. In contrast, arterial pressure during heart relaxation (diastole) is the diastolic component, the lowest arterial pressure in the cycle. Mean arterial pressure is an average pressure over the entire cardiac cycle, not the peak. Pressure in the veins is not what the arterial systolic reading measures.