Fractal angle modality patterns in RRI and respiration signal of healthy subjects responding to orthostasis and slow breathing

We explored influence of slow breathing and orthostasis on angular indices that correspond to slopes of regression lines of detrended fluctuation analysis (DFA) of RR intervals and respiration signal. The tool for our exploration was probability density estimation (PDE). By applying it, we got insights about body posture and breathing regime induced group behavioral patterns of these DFA angles and that these patterns have certain physiological meaning. Mainly, obtained PDE patterns (unimodality, bimodality etc) reflect ergo/tropho-tropic character of sympathetic and parasympathetic adaptive modulation with respect to changes of physical and physiological conditions of diverse physiological states.