<p>This exploratory single-session case study aimed to gain insight into the added value of measuring heart rate variability in enhancing the understanding of the emotions and meanings involved in the dialog between a client with an anxiety disorder and a psychotherapist. Heart rate variability was measured in both clients and psychotherapists, and the root mean square of successive differences in heartbeats was used as a proxy to parasympathetic nervous system activation. Associations between the themes of the dialog and the psychophysiological markers were examined. The study demonstrated that changes in heart rate variability exhibited logical associations with ongoing dialog themes. The study yielded insights into the client’s emotional state, particularly in instances where she expressed guilt- and shame-provoking emotions and thoughts, and when the psychotherapist sought to provide empathy and validation that the client was unable to receive or accept. The first finding suggests that parasympathetic activation may increase as repressed thoughts or emotions are verbalized. The latter finding supports the claim that sympathetic activation may be elevated in response to experiences that do not align with an individual’s identity narrative. Additionally, the psychophysiological data suggested that the client’s emotions were more intense than could be inferred from her voice or facial expressions. Notwithstanding the necessity to exercise caution when interpreting the findings based on a single psychotherapy session, the results suggest that psychophysiological indices have the potential to enhance understanding of client and psychotherapist processes during therapeutic interactions. Thus, further research using psychophysiological markers in clinical settings seems justified.</p>