The impact of posttraumatic stress disorder versus resilience on nocturnal autonomic nervous system activity as functions of sleep stage and time of sleep

Abstract

Posttraumatic stress disorder (PTSD) has been associated with sleep disturbances including alterations in sleep stages and recently, elevated nocturnal autonomic nervous system (ANS) arousal (i.e., dominance of the sympathetic nervous system over the parasympathetic nervous system). Data suggest that sleep contributes to the regulation of ANS activity. In our previous ambulatory heart rate variability (HRV) monitoring study, strong relationships between sleep and nocturnal ANS activity in resilient participants (i.e., individuals who had never had PTSD despite exposure to high-impact trauma) were not seen with PTSD. In this study, we examined the impact of PTSD vs. resilience on ANS activity as a function of sleep stage and time of sleep. Participants (age 18–35) with current PTSD (n = 38) and resilience (n = 33) completed two overnight polysomnography recordings in a lab setting. The second night electrocardiogram was analyzed for frequency domain HRV parameters and heart rate within rapid-eye-movement (REM) and non-REM (NREM) sleep periods. Results indicated that ANS arousal indexed by HRV was greater during REM compared with NREM sleep and that the REM–NREM difference was greater in the PTSD than in the resilient participants. This effect of PTSD was reduced to non-significance when analyses controlled for REM sleep percentage, which was lower with PTSD. Exploratory analyses revealed that the REM–NREM difference in HRV was correlated with REM sleep percentage in resilient participants, but not with PTSD. In contrast with our data from home settings, the present study did not find increased overall nocturnal ANS arousal with PTSD. Analyses did reveal higher heart rate during initial NREM sleep with more rapid decline over the course of NREM sleep with PTSD compared with resilience. Findings suggest that elevated ANS arousal indexed by heart rate with PTSD is specific to the early part of sleep and possible impairment in regulating ANS activity with PTSD related to REM sleep.

Posttraumatic stress disorder diagnosis is associated with reduced parasympathetic activity during sleep in US veterans and military service members of the Iraq and Afghanistan wars

“…This finding is generally consistent with prior studies suggesting reduced parasympathetic function during sleep in those with PTSD [19,20]. As discussed above, Kobayashi and colleagues [17] conducted the only other study examining HF-HRV by sleep type in those with PTSD. In contrast with our study, Kobayashi and colleagues found a group-by-sleep-type interaction with the PTSD group having greater REM-NREM differences in HF-HRV than resilient individuals.…”

“…Only one study has examined trends in HF-HRV across sleep in those with PTSD. Kobayashi and colleagues (discussed above) [17] found a significant decline in HF-HRV across successive NREM cycles across the night, but the rate of decline did not differ between groups. No changes were found in HF-HRV activity across successive REM sleep cycles.…”

“…Specifically, they posited that since REM percentage explained group differences in REM-NREM ANS activity in their sample, REM sleep may play a role in the decrements in ANS regulation during sleep observed in those with PTSD. They also suggested that, since their laboratory-based polysomnography (PSG) findings [17] differed from their prior findings employing ambulatory PSG [19], the assessment environment (home vs. lab) may be an important consideration when examining sleep ANS activity in those with PTSD.…”

“…We found only one prior study examining HF-HRV during sleep in those with PTSD or PTSD symptoms wherein findings were examined as a function of sleep type (NREM vs. REM) and time of night. Kobayashi and colleagues [17] examined ANS activity during sleep in a sample of healthy young African American adults (age 18-35 years) who had been exposed to a high impact traumatic event. They found that individuals meeting either full diagnostic criteria for PTSD or subthreshold PTSD criteria had greater REM-NREM differences in laboratory-based ANS activity as indexed by LF/HF HRV and HF-HRV compared to resilient individuals (those who never met diagnostic criteria for PTSD despite exposure to trauma).…”

Cardiac Autonomic Modulations and Psychological Correlates in the Yukon Arctic Ultra: The Longest and the Coldest Ultramarathon

“…Subjects exposed to extreme conditions and environments display astounding adaptive potential, which ultimately ensures optimal adjustment to current organismic demands and external stress (Kälin et al, 2012 ; Gunga, 2014 ). Assessment of autonomic cardiac modulation by means of heart rate variability (HRV) has shown to be a reliable tool to evaluate not only physiological changes (Taralov et al, 2015 ; Kobayashi et al, 2016 ), but also psychological aspects of human reactive adaptation to different stressors (Souza et al, 2013 ). Therefore, HRV assessment may describe human resilience, as it represents a bridge between physiology and psychology, and, by integrating these two aspects, it mirrors human adaptive ability (Thayer et al, 2009 ; Spangler and Friedman, 2015 ).…”