What do the top number (115) and bottom number (75) represent in a blood pressure reading?

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Multiple Choice

What do the top number (115) and bottom number (75) represent in a blood pressure reading?

Two numbers on a blood pressure reading reflect pressures in the arteries at different moments of the heartbeat. The top number is the systolic pressure—the peak pressure when the heart contracts and ejects blood. The bottom number is the diastolic pressure—the pressure when the heart relaxes between beats. So for 115 over 75, 115 is the systolic value and 75 is the diastolic value. That’s why the correct description is systolic/diastolic. Other terms describe different things: mean arterial pressure is a single averaged value that approximates overall perfusion, and pulse pressure is simply the difference between the top and bottom numbers (115 − 75 = 40 mm Hg in this example). The order matters because the top value always corresponds to systolic pressure, and the bottom to diastolic.

Two numbers on a blood pressure reading reflect pressures in the arteries at different moments of the heartbeat. The top number is the systolic pressure—the peak pressure when the heart contracts and ejects blood. The bottom number is the diastolic pressure—the pressure when the heart relaxes between beats. So for 115 over 75, 115 is the systolic value and 75 is the diastolic value. That’s why the correct description is systolic/diastolic.

Other terms describe different things: mean arterial pressure is a single averaged value that approximates overall perfusion, and pulse pressure is simply the difference between the top and bottom numbers (115 − 75 = 40 mm Hg in this example). The order matters because the top value always corresponds to systolic pressure, and the bottom to diastolic.

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