Respiratory Sinus Arrhythmia: Physiological Basis, Quantitative Methods, and Clinical Implications

Abstract

Of the many observable physiological oscillations, the oscillations in the heart rate pattern associated with respiration (i.e. respiratory sinus arrhythmia) are the most relevant to psychophysiological research. The use of respiratory sinus arrhythmia in psychophysiological research may be justified by the facts that: (1) neurophysiology justifies the measurement of the amplitude of respiratory sinus arrhythmia as an index of cardiac vagal tone; (2) the amplitude of respiratory sinus arrhythmia indexes general central nervous system status; and (3) the changing amplitude of respiratory sinus arrhythmia parallels psychological constructs often used in psychophysiological paradigms such as sustained attention and stress.