High heart rate variability buffers the effect of attachment insecurity on sleep quality

Sleep quality is an important health-protective factor. Psychosocial factors, including attachment orientation, may be valuable for understanding who is at risk of poor sleep quality and associated adverse health outcomes. High attachment anxiety is reliably associated with adverse health outcomes, while high attachment avoidance is associated with adverse health outcomes when co-occurring with poor self-regulatory capacity, indexed by heart rate variability (HRV). We examined the associations between attachment anxiety, attachment avoidance, HRV, and sleep quality. Using longitudinal data from a sample of 171 older adults measured four times over one year (M = 66.18 years old; 67.83% women), we separated the between-person variance (which we call "trait") and within-person variance (which we call "state") for attachment anxiety, attachment avoidance, and HRV (via the root mean square of successive differences). Sleep quality was measured with the Pittsburgh Sleep Quality Index. Higher trait attachment anxiety was associated with poorer global sleep quality (B = 0.22, p = .005). Higher state attachment avoidance was associated with poorer sleep quality (B = -0.13, p = .01), except for those with higher trait HRV. Higher state attachment anxiety was associated with poorer sleep quality (B = -0.15, p = .002), except for those with higher or mean trait HRV. Higher trait attachment anxiety was associated with poorer sleep quality (B = -0.31, p = .02), except for those with higher trait HRV. High trait HRV mitigated the adverse effects of attachment insecurity on sleep quality. Our results suggest that people with high trait HRV had greater self-regulation capacity, which may be able them to enact emotion regulation strategies effectively.