Heart rate variability: Pre-deployment predictor of post-deployment PTSD symptoms

Abstract

Heart rate variability is a physiological measure associated with autonomic nervous system activity. This study hypothesized that lower pre-deployment HRV would be associated with higher post-deployment post-traumatic stress disorder (PTSD) symptoms. Three-hundred-forty-three Army National Guard soldiers enrolled in the Warriors Achieving Resilience (WAR) study were analyzed. The primary outcome was PTSD symptom severity using the PTSD Checklist - Military version (PCL) measured at baseline, 3- and 12-month post-deployment. Heart rate variability predictor variables included: high frequency power (HF) and standard deviation of the normal cardiac inter-beat interval (SDNN). Generalized linear mixed models revealed that the pre-deployment PCL*ln(HF) interaction term was significant (p<0.0001). Pre-deployment SDNN was not a significant predictor of post-deployment PCL. Covariates included age, pre-deployment PCL, race/ethnicity, marital status, tobacco use, childhood abuse, pre-deployment traumatic brain injury, and previous combat zone deployment. Pre-deployment heart rate variability predicts post-deployment PTSD symptoms in the context of higher pre-deployment PCL scores.

Keywords: Post-traumatic stress disorder (PTSD); combat stress; heart rate variability; longitudinal; military; prediction; risk factors.

Published by Elsevier B.V.

Figures

Fig. 1

Predicted 3- and 12-month Post-deployment PTSD Severity by Pre-deployment PTSD Severity and High Frequency (HF) Power HRV.1 1Rationale for pre-deployment PCL levels: 50 = common cutoff for positive PTSD screen in surveillance studies(Hoge et al., 2004; Terhakopian et al., 2008) and 34 = recommended cutoff for clinical screening for PTSD. (Bliese et al., 2008)