When measuring blood pressure, which number represents the pressure in the arteries when the heart is at rest?

The diastolic number represents the pressure in the arteries when the heart is at rest, specifically during the phase of the cardiac cycle when the heart is between beats and filling with blood. This pressure reflects the minimum arterial pressure and is crucial for understanding overall cardiovascular health.

In contrast, the systolic number indicates the pressure in the arteries when the heart is actively pumping blood, which occurs during heartbeats. Terms like hypertension and normal refer more broadly to conditions of blood pressure rather than the specific phases of the cardiac cycle and do not pinpoint the resting pressure measured between heartbeats. Therefore, the diastolic measurement is specifically significant for assessing how relaxed or resistant the circulatory system is when the heart is not in the active phase of contraction.