Stability of respiratory sinus arrhythmia in children and young adolescents: a longitudinal examination.

The stability of children's baseline respiratory sinus arrhythmia (RSA) and RSA regulation were examined longitudinally, with a 2-year lag between each of two waves of data collection. Associations between baseline RSA and RSA regulation also were examined in this study. During two laboratory sessions, 2 years apart, children were exposed to two stressors: exposure to an audiotaped conflict between two adults and a problem-solving task in which the child had to trace a star while looking into a mirror. Measures of baseline RSA and RSA regulation during the two stressors were obtained. Baseline RSA and, to a lesser extent, RSA regulation to the star-tracing task were stable over time. Furthermore, baseline RSA was associated with increased RSA suppression to the laboratory stressors. These results augment the scant longitudinal literature on psychophysiological development in elementary-school-age children and young adolescents, and support the proposition that some aspects of RSA constitute stable individual differences at the ages examined.