Autonomic-cardiorespiratory regulation: a physiology-based mathematical model.

This paper presents a novel physiology-based mathematical model of autonomic-cardiorespiratory regulation described by a set of three nonlinear, coupled differential equations. We improved our previously proposed autonomic-cardiac regulation model by considering neuromechanical and mechanical coupling of cardiovascular and respiration systems including lung stretch-receptor reflex and venous return variation. We also introduced a differential equation describing respiration rate regulation which mainly originates in the medullary respiratory center. The results of simulation experiments suggest that the venous return variation generates a higher perturbation on heart rate and blood pressure than lung stretch-receptor reflex. The proposed model is also powerful in determining and removing direct respiratory impacts on parasympathetic activation tone to accurately extract parasympathetic activity caused by emotional states and environmental conditions.