Hemodynamic response to exercise in supine and standing attitudes: an integrated model

Dynamic exercise influences the cardiovascular system in various ways, and the attitude of our body also affect the hemodynamics. In this study, we adopted and integrated a double-closed-loop model consisting of the cardiovascular system (CVS), and the autonomic nervous system (ANS), along with the mathematical models of exercise and body attitude for hemodynamic prediction and cardiovascular regulation. The CVS-ANS-exercise coupling model is validated with two cases of the hemodynamic response to exercises: two different kinds of exercises (one-leg extension and one-leg cycling), and the recovery from one-leg cycling under two different attitudes (supine and standing). The results show that the transition of blood pressure varies during different exercises; the recovery from exercise is more rapid in the supine attitude. We confirmed by comparing simulation results to experimental data, that the simulation model in this study is effective. Furthermore, a simulation-based exercise model can potentially reduce the risk of performing an exercise test in clinical practice.