Objectives: First evidence suggests that lower heart rate variability (HRV) is associated with more cognitive control deficits, a risk factor for the development of intrusive memories. The aim of this study was to determine whether high-frequency (HF) and low-frequency/high-frequency (LF/HF) ratio components of HRV at rest before an intrusion-inducing stressor would predict consecutive intrusive memories.Methods: Healthy female participants (n = 60) watched an established distressing film which induced intrusions. HF and LF/HF ratio were measured for 5 min prior to the stressor. The number of consecutive intrusions resulting from the distressing film was assessed throughout the following 4 days.Results: The main effect LF/HF ratio was associated with more intrusive memories, whereas, the main effect HF was associated with more intrusions on a trend level. The time × HF and time × LF/HF ratio interactions were significant, indicating a different course of number of intrusions over the 4 days depending on HF and LF/HF ratio. The regression-based parameter estimates revealed a significant association of lower HF and number of intrusions on days 1 and 2 and a significant association of higher LF/HF (i.e. lower HRV) and number of intrusions on day 1.Conclusions: The results suggest that higher baseline LF/HF ratio (i.e. lower HRV) predicts more intrusive memories in healthy women after watching a distressing film. Furthermore, the results suggest that women with lower baseline HF and higher LF/HF ratio recover at a slower rate from watching the distressing film by showing a delayed decrease in intrusive memories. Our findings support the notion that lower baseline HRV before a trauma might be a vulnerability factor for subsequent intrusive memories.
Keywords: Intrusive memories; PTSD; film paradigm; heart rate variability; parasympathetic nervous system.