Critical re-evaluation of heart rate variability as a predictor of posttraumatic stress disorder: a narrative review.

Posttraumatic stress disorder (PTSD) has been associated with alterations in heart rate variability (HRV) following exposure to potentially psychologically traumatic events . HRV has long been widely believed to reflect the autonomic nervous system (ANS) and associated modulatory cardiac impacts; however, recent evidence does not support the association. The current narrative review evaluates the current literature on HRV in relation to PTSD and other posttraumatic stress injuries (PTSI), focusing solely on empirically observed changes in HRV metrics, independent of unverified physiological interpretations. The current review highlights substantial methodological heterogeneity, inconsistent measurement approaches, and the lack of longitudinal data needed to establish causality. Results suggest that, while HRV is altered in individuals with PTSD compared to controls, the differences are small, variable, and context dependent. Substantial limitations in measurement reliability and interpretive validity preclude recommending HRV as a standalone clinical or screening tool for assessing PTSI currently. Furthermore, the HRV results should be discussed as a direct measure of a physiological signal, not as a theoretical ANS construct.