# Stroke volume

 Articles WikiDoc Resources for Stroke volume

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

## Overview

Stroke volume is the amount of blood pumped by the left ventricle of the heart in one contraction.

The stroke volume is not all of the blood contained in the left ventricle. The heart does not pump all the blood out of the ventricle. Normally, only about two-thirds of the blood in the ventricle is put out with each beat. What blood is actually pumped from the left ventricle is the stroke volume and it, together with the heart rate, determines the cardiac output.

## Calculation

Its value is obtained by subtracting end-systolic volume (ESV) from end-diastolic volume (EDV) for a given ventricle:

${\displaystyle SV=EDV-ESV}$

In a healthy 70-kg man, the left ventricular EDV is 120 ml and the corresponding ESV is 50 ml, giving a stroke volume of 70 ml.

## Determinants

Men, on average, have higher stroke volumes than women due to the larger size of their hearts. However, stroke volume depends on several factors such as heart size, contractility, duration of contraction, preload (end-diastolic volume), and afterload.

### Exercise

Prolonged aerobic exercise may also increase stroke volume, which frequently results in a slower heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.