Respiratory sinus arrhythmia predicts perceived therapy process of a group-based acceptance and commitment therapy intervention.

Engagement in psychotherapy is partially contingent on present-moment focus, mindfulness, and emotion regulation skills. These skills can be linked to parasympathetic functioning with theoretical explanations provided by polyvagal and neurovisceral integration theories. The specific aims of this project were to evaluate relationships between a measure of parasympathetic functioning (respiratory sinus arrythmia [RSA]) and measures of client reports of engagement in an experiential and emotionally evocative group-based intervention. Twenty-one community residents received group-based acceptance and commitment therapy (ACT) for work stress. RSA was measured 1 week before the intervention. Client ratings of relationship support, task focus, and hindering experiences were assessed after each session. Results indicated that clients perceived the ACT intervention to be supportive, task-focused, and without significant therapy-hindering experiences. Higher levels of RSA were significantly associated with higher levels of relationship support. These results support predictions derived from the polyvagal and neurovisceral integration theories.