Physiological singularities in respiratory and cardiac dynamics

Chaotic nonlinear dynamics have been extensively used to analyze the complexities of physiological systems in health and disease. Many assertions in this regard, however, fail on the basis of (a) mathematical assumptions, and (b) basic understanding of the physiology involved. Our preliminary research using experimental data from breathing patterns as well as electrocardiographic signals suggest that some of these dynamics can be understood as oscillators with singular points from which emanate multi-choice responses to excitations. Deviations in the distributions of responses may reflect pathology.