Blood pressure is a fundamental measure of health, reflecting the force with which blood circulates through the body’s vessels. It consists of two distinct numbers, both providing important insights into cardiovascular function.
Defining Systolic Blood Pressure
Systolic blood pressure (SBP) is the upper number in a blood pressure reading, indicating the pressure within the arteries when the heart contracts. This phase, known as systole, occurs as the heart’s ventricles pump blood into the arterial system. It measures the maximum pressure exerted on artery walls during this ejection.
During systole, the heart actively works to distribute oxygenated blood to all organs and tissues. The ability of arteries to expand and accommodate this surge of blood influences the systolic reading. Stiffer arteries, often associated with aging or cardiovascular conditions, can result in higher systolic pressures as the heart must generate more force to overcome resistance.
How Systolic Pressure is Measured
Measuring blood pressure involves a device called a sphygmomanometer, commonly known as a blood pressure cuff. This device uses an inflatable cuff wrapped around the upper arm. The cuff is inflated until it temporarily stops blood flow through the brachial artery.
As the air is slowly released from the cuff, a healthcare professional or automated device listens for the first sounds of blood flow returning through the artery. This initial sound indicates the systolic pressure, which is recorded in millimeters of mercury (mmHg). Automated devices use sensors to detect these pressure changes and display the reading digitally.
Understanding Your Systolic Readings
Blood pressure readings are categorized to assess cardiovascular health, with specific ranges defining normal, elevated, and hypertensive levels. A normal systolic pressure is considered less than 120 mmHg. Elevated blood pressure is classified when systolic readings fall between 120 and 129 mmHg, with a diastolic pressure less than 80 mmHg.
Hypertension, or high blood pressure, is divided into stages. Stage 1 hypertension is diagnosed when systolic pressure consistently ranges from 130 to 139 mmHg, or diastolic pressure is between 80 and 89 mmHg. Stage 2 hypertension indicates more severe elevation, with systolic readings of 140 mmHg or higher, or diastolic readings of 90 mmHg or higher.
Why Systolic Pressure Matters
Systolic pressure is an important indicator of cardiovascular health because consistently high readings can lead to health complications. Uncontrolled high systolic pressure can damage blood vessels and increase the risk of heart attack, stroke, and kidney disease. It can also contribute to heart failure, where the heart’s pumping ability weakens over time.
Even when diastolic pressure remains normal, an elevated systolic reading, known as isolated systolic hypertension, can still pose health risks, particularly for older adults. Conversely, very low systolic pressure (hypotension) can lead to symptoms like dizziness, fainting, and confusion, as organs may not receive adequate blood flow. Persistent low systolic pressure with symptoms requires medical evaluation to prevent potential organ damage.