Abstract: An apparatus a method for determining stroke volume by bioimpedance from a person having two or more spaced apart alternating current flow electrodes positionable on a person and two or more spaced apart voltage sensing electrodes positionable on the person and between the alternating current flow electrodes. A constant magnitude alternating current source is electrically connectable to the alternating current flow electrodes. A voltmeter is electrically connectable to the voltage sensing electrodes and configured to generate a voltage signal Z from a voltage sensed by the voltage sensing electrodes. A processing unit is electrically connectable with the voltmeter and configured to determine a stroke volume (SV) using the voltage signal Z and at least one of six equations.