What is Stroke Volume?

Stroke Volume (SV) is a critical hemodynamic parameter in cardiology that measures the volume of blood pumped out of the left ventricle of the heart during a single systolic contraction. Understanding your stroke volume is essential for assessing cardiac output and overall cardiovascular health. It is typically measured in milliliters (mL).

How to Calculate Stroke Volume

The standard formula for calculating stroke volume is straightforward: SV = EDV - ESV. In this equation, EDV stands for End-Diastolic Volume, which is the amount of blood in the ventricle just before it contracts. ESV stands for End-Systolic Volume, which is the amount of blood remaining in the ventricle after it has finished contracting. The difference between these two values represents the amount of blood successfully ejected into the systemic circulation.

Normal Range for Stroke Volume

For a healthy adult weighing approximately 70kg, the average stroke volume is roughly 70 mL. However, this value can vary significantly based on physical fitness, age, gender, and heart size. Elite athletes often have higher stroke volumes because their heart muscle is more efficient and can pump more blood with each beat, allowing for a lower resting heart rate.

Why is Stroke Volume Important?

Clinicians use stroke volume to determine Cardiac Output (CO = SV × Heart Rate). If a person has a low stroke volume, the heart must beat faster to maintain adequate blood flow to the body's organs. Chronic issues with low stroke volume can be indicative of heart failure, valve disease, or dehydration. Conversely, monitoring improvements in stroke volume is a key indicator of cardiovascular conditioning progress in fitness programs.

Frequently Asked Questions

What factors affect stroke volume? Three primary factors influence SV: Preload (the stretching of the heart muscle), Contractility (the force of the contraction), and Afterload (the resistance the heart must pump against).

Can I calculate stroke volume at home? Accurate EDV and ESV measurements usually require medical imaging like an echocardiogram or MRI. However, if you have these values from a recent medical report, our calculator can help you track your stats.