Systolic Blood Pressure
Systolic blood pressure is the amount of pressure that blood exerts on vessels while the heart is beating. In a blood pressure reading (such as 120/80), it is the number on the top. If the top and bottom blood pressures are both too high, a person is said to have high blood pressure. If only the top number is higher than 140, the person has a condition called isolated systolic hypertension.
What Is Systolic Blood Pressure?
Blood pressure is the amount of force (pressure) that blood exerts on the walls of the blood vessels as it passes through them. Two pressures are measured for a blood pressure reading:
- Systolic blood pressure is a measure of blood pressure while the heart is beating.
- Diastolic pressure is a measure of blood pressure while the heart is relaxed.
How Is It Measured?
To measure your systolic blood pressure, your healthcare provider will usually use a device called a sphygmomanometer. A fabric cuff is wrapped around your arm and then inflated slightly. The blood pressure is measured on a gauge attached to the cuff. The healthcare provider reads the numbers that appear on the gauge as air is released from the cuff. Blood pressure can also be measured with a blood pressure machine.
The two numbers that measure your blood pressure are written like a fraction: one number on top and one on the bottom. For example, what many people consider normal blood pressure is read as 120/80. The number on top is the systolic blood pressure. It measures the pressure inside your blood vessels at the moment your heart beats. The number on the bottom is your diastolic pressure, which measures the pressure in your blood vessels between heartbeats, when your heart is resting.