Sleep quality moderates the association between family bereavement and heart rate variability.

Two separate bodies of literature point to the link between family bereavement and cardiovascular health and between sleep quality and cardiovascular outcomes. However, less is known about the joint influence of family bereavement and sleep quality on cardiovascular functioning. The aims of this study were to examine the relationships between experiencing the death of a family member and heart rate variability (HRV) and to further explore whether these associations differ by sleep quality. Using data from the Midlife in the United States (MIDUS) Biomarker Project, the sample for this study included respondents who experienced the death of an immediate family member - father, mother, spouse, sibling, or child - within a year before the Biomarker project and those who did not experience any deaths (N = 962). We used two measures of HRV and sleep quality was measured using the Pittsburgh Sleep Quality Index. Results showed that experiencing the death of a family member was associated with worse HRV only among those with poor sleep quality and not for those with good sleep quality. These results suggest that poor sleep quality may indicate psychophysiological vulnerability for those who experienced the death of a family member. Interventions to improve sleep quality could be effective in enhancing cardiovascular health of bereaved individuals.