Examining the Crux of Autonomic Dysfunction in Posttraumatic Stress Disorder: Whether Chronic or Situational Distress Underlies Elevated Heart Rate and Attenuated Heart Rate Variability.

OBJECTIVE: Posttraumatic stress disorder (PTSD) has been linked to elevated heart rate (HR) and reduced heart rate variability (HRV) in cross-sectional research. Using ecological momentary assessment and minute-to-minute HRV/HR monitoring, we examined whether cross-sectional associations between PTSD symptom severity and HRV/HR were due to overall elevations in distress levels or to attenuated autonomic regulation during episodes of acute distress.
METHODS: Two hundred nineteen young adults (18-39 years old), 99 with PTSD, underwent 1 day of Holter monitoring and concurrently reported distress levels via ecological momentary assessment. Using multilevel modeling, we examined the associations between momentary distress and the 5-minute means for low-frequency (LF) and high-frequency (HF) HRV and HR immediately following distress ratings, and whether PTSD symptom severity moderated these associations.
RESULTS: Compared with the controls, participants with PTSD recorded higher ambulatory distress (mean [standard deviation] = 1.7 [0.5] versus 1.2 [0.3], p < .001) and HR (87.2 [11.8] versus 82.9 [12.6] beats/min, p = .011), and lower ambulatory LF HRV (36.9 [14.7] versus 43.7 [16.9 ms, p = .002) and HF HRV (22.6 [12.3] versus 26.4 [14.6] milliseconds, p = .043). Overall distress level was not predictive of HR or HRV (p values > .27). However, baseline PTSD symptom severity was associated with elevated HR (t(1257) = 2.76, p = .006) and attenuated LF (t(1257) = -3.86, p < .001) and HF (t(1257) = -2.62, p = .009) in response to acute momentary distress.
CONCLUSIONS: Results suggest that PTSD is associated with heightened arousal after situational distress and could explain prior findings associating PTSD with HR/HRV. Implications for treatment and cardiovascular risk are discussed.