Systolic Blood Pressure: Understanding Readings & What They Mean

In the cardiac cycle in which the heart beats, blood pumps throughout the body. This pumping action creates a force, or pressure, which is measured in two parts--the systolic and the diastolic. The systolic is the highest pressure created in the cycle, and occurs after the contraction of the heart's left ventricle.

Getting a Reading

• The cuff and instrument used to take your blood pressure is called a sphygmomanometer. As the inflating cuff tightens around your arm, it stops the blood flow in your artery. Letting the air out of the cuff allows a healthcare professional listening through a stethoscope to hear a thumping sound.

The Systolic Beat

• That thumping sound represents your systolic pressure. Systolic blood pressure is what results from your heart muscle contracting.

The Top Reading

• Whether measuring blood pressure manually or with a machine, the top (or first) number is the systolic reading. Normally, this is the larger number of the two.

The Bottom Reading

• Between contractions, the heart relaxes, or dilates. This phase of the cardiac cycle measures diastolic blood pressure. In manual readings, a healthcare professional listens for when the thumping sound starts to fade to take the diastolic measurement.

Range

• Your body does not maintain a constant blood pressure. So when measuring blood pressure, it is normal to have variations throughout the day. In general, a systolic reading below 130 is normal. A high normal reading is between 130 and 139. And anything from 140 and higher is considered high.