Effect of expressive and neutral writing on respiratory sinus arrhythmia response over time.

BACKGROUND AND OBJECTIVES: Parasympathetic activity, as indexed by respiratory sinus arrhythmia (RSA), underlies key aspects of emotional and cognitive self-regulation. Examining time-varying RSA response during expressive writing about trauma may help inform theory about mechanisms of this intervention. The present study investigated changes in RSA during expressive writing. METHODS: Participants (N = 246, Mage = 21.5 years, 72% female) were randomly assigned to expressive or neutral writing conditions and wrote for three 20-min sessions. RSA was measured continuously during the first and third writing session. RESULTS: Linear mixed model analyses of RSA changes within and across sessions by writing groups found that neutral writers, but not expressive writers, exhibited change in RSA. The overall RSA changes during expressive and neutral writing are consistent with theory about the relationship between cognitive and emotional processing mechanisms and vagal activation. LIMITATIONS: As the present study was not a clinical sample selected on trauma exposure, findings should be considered preliminary. Additionally, engagement of affective and cognitive processes was only hypothesized, as manipulation checks were not performed. CONCLUSIONS: The present study illustrates the benefits of examining changes in RSA over time. Future work with clinical samples should include additional measures and tasks to better define these mechanisms and rule out alternative hypotheses.