The cardiac output and stroke volume of a healthy person was estimated using a 3D fluid-structure interaction (FSI) simulation coupled with an echocardiogram Doppler (echo-Doppler) during exercising and resting. The geometry, dimensions, and blood flow through the aortic valve were measured using the echo-Doppler. A 3D FSI simulation was modeled using an arbitrary Lagrangian-Eulerian mesh. The 3D FSI cardiac output and stroke volume results were 15.4% lower than Doppler results when brachial pressures applied with differences between brachial, central, and left ventricular pressures. While without considering these brachial pressures differences, the discrepancy between the FSI cardiac output and stroke volume results with Doppler increased to 22.3% and 26.2%, respectively. Eventually, the comparisons of the 3D FSI results and clinical measurements demonstrated that numerical methods can be a potential computational tool to estimate cardiac output and stroke volume for different heart rates when they coupled with the clinical measurements.