Posttraumatic Stress, Heart Rate Variability, and the Mediating Role of Behavioral Health Risks

Abstract

Objective Posttraumatic stress disorder (PTSD) has been linked to reduced heart-rate variability (HRV), which is in turn a risk factor for cardiovascular disease and death. Although hyperarousal and anxiety are thought to underlie this association, behavioral health risks, including smoking, alcohol dependence, obesity, and sleep disturbance, represent potential mechanisms linking PTSD and HRV. Methods To test this hypothesis, a combination of short-term laboratory-based and 24-hour ambulatory measures of HRV were collected from 227 young adults (18-39 years old), 107 of whom were diagnosed with PTSD. Latent variable modeling was used to assess the relationship of PTSD symptoms with HRV along with potential behavioral health mediators. Results PTSD symptoms were associated with reduced HRV, β = -.21, p = .002. However, this association was reduced in models that adjusted for cigarette consumption and history of alcohol dependence, and was rendered non-significant in a model adjusting for sleep disturbance. Independent mediation effects were deemed significant via bootstrapping analysis. Together the three behavioral health factors (cigarette consumption, history of alcohol dependence, and sleep disturbance) accounted for 94% of the shared variance between PTSD symptoms and HRV. Abdominal obesity was not a significant mediator. Conclusions These results indicate that behavioral factors—specifically smoking, alcohol overuse, and sleep disturbance—mediate the association between PTSD and HRV-based indices of autonomic nervous system dysregulation. Benefits from psychiatric and psychological interventions in PTSD may therefore be enhanced by including modification of health behaviors.

Exploring the relationship between posttraumatic stress disorder symptoms and momentary heart rate variability

“…The sample was comprised of only PTSD individuals; thus results extend previous findings comparing PTSD and non-PTSD individuals (Dennis et al, 2014) to within group HRV variability on PTSD symptom severity. The momentary assessment method and the within-group severity analysis provides further evidence that PTSD symptoms are significantly associated with HRV.…”

“…Data were from a larger study on trauma and health (Dennis et al, 2014). Exclusion criteria included age <18 or >39 years, the presence of an organic mental disorder, schizophrenia, bipolar I (mixed) and II, lifetime PTSD without current PTSD, current substance abuse/dependence, current major depressive disorder without PTSD, pregnancy, HIV/AIDS, and an uncontrolled condition.…”

“…Although PTSD has been associated with reduced HRV (Dennis et al, 2014; Shah, 2013), it remains unclear whether PTSD is directly related to reduced PSNS through PTSD symptomatology (e.g., hyperarousal) or via an indirect effect of lifestyle factors (e.g., smoking; Dennis et al, 2014). Findings that PTSD is associated with an exaggerated withdrawal of PSNS activity and an excessive SNS response to trauma cues suggest that the experience of PTSD’s core symptoms may directly underlie ANS dysregulation (Norte et al, 2013; Southwick et al, 1999; Kosten et al, 1987; Blanchard et al, 1991; Liberzon et al, 1999).…”

An investigation of vago-regulatory and health-behavior accounts for increased inflammation in posttraumatic stress disorder

“…Data were collected between August 2008 and September 2013. Previous findings from this sample include linkages between PTSD and orthostatic hypotension (39), decreased HRV (32), and dyslipidemia (40). …”

“…Note that BMI was not tested as a potential mediator of PTSD symptom severity and inflammation in light of previously published analyses from this sample indicating that PTSD symptom severity was unassociated with obesity (32). Years since initial exposure to a traumatic event resulting in fear, helplessness, and horror was additionally controlled to assess the effect of PTSD status on inflammation independent of trauma exposure.…”