When someone measures your blood pressure, you’ll see two numbers listed. The top number is called the “Systolic Blood Pressure” and the bottom number is called the “Diastolic Blood Pressure.” The Systolic number represents the force that your heart generates while the muscle is squeezing down, or contracting to force blood into the circulatory system.

The second number of your blood pressure reading is called your “Diastolic Blood Pressure.” Basically, it represents the pressure in your circulatory system when your heart is relaxing between beats.

Blood pressure measurements are made by placing an inflatable cuff around one of your arms and listening over the artery with a stethoscope. Attached to the cuff is a pressure gauge.

The cuff is inflated to the point that it briefly stops the blood-flow. The air is released slowly, and your provider listens with a stethoscope. When the pressure of the blood coming from the heart beating is equal to the pressure of the cuff, small amounts of blood flow through and make a “whooshing” sound. Your provider listens carefully for this sound while watching the blood pressure gauge, which gives a reading in millimeters of mercury. The first measurement is always the top number, which represents the systolic blood pressure. It has a normal range of 90-130 millimeters of mercury.

When the last pulse is heard through the stethoscope, the blood is flowing smoothly through the artery and no more “whooshing” sounds are heard. Your provider records the number shown on the pressure gauge at that moment. This is the bottom number of a blood pressure measurement, or your diastolic blood pressure. It has a normal range of 60-90 millimeters of mercury. The diastolic blood pressure represents the amount of pressure in the circulatory system when your heart is resting between beats.

There is a wide range of blood pressure readings in the general population. On the average, younger people have lower blood pressures than older people and men have higher blood pressures than women.

Although we most commonly see elevations in both the systolic and diastolic blood pressures, elevation of systolic blood pressure can be seen alone, particularly in people over the age of 65.