Effects of Daily Posttraumatic Stress Disorder Symptoms on Heart Rate Variability

OBJECTIVE: Posttraumatic stress disorder (PTSD) is common, debilitating, and associated with an increased risk of health problems, including cardiovascular disease. PTSD is related to poor autonomic function indicated by reduced heart rate variability (HRV). However, very little work has tested the timescale or direction of these effects, given that most evidence comes from cross-sectional studies. Documentation of when effects occur and in what direction can shed light on mechanisms of cardiovascular disease risk and inform treatment. The present study of 169 World Trade Center responders, oversampled for PTSD, tested how daily PTSD symptoms were associated with autonomic function as reflected through HRV. METHODS: Participants ( N = 169) completed surveys of PTSD symptoms three times a day at 5-hour intervals for 4 days while also wearing ambulatory monitors to record electrocardiograms to derive HRV (i.e., mean absolute value of successive differences between beat-to-beat intervals). RESULTS: HRV did not predict PTSD symptoms. However, PTSD symptoms during a 5-hour interval predicted reduced HRV at the next 5-hour interval ( β = -0.09, 95% confidence interval = -0.16 to -0.02, p = .008). Results held adjusting for baseline age, current heart problems, and current PTSD diagnosis. CONCLUSIONS: Findings underscore growing awareness that PTSD symptoms are not static. Even their short-term fluctuations may affect cardiovascular functioning, which could have more severe impacts if disruption accumulates over time. Research is needed to determine if momentary interventions can halt increases in PTSD symptoms or mitigate their impact on cardiovascular health.