Examination of positive states of mind and heart rate variability: Stress appraisals as a mechanism in trauma-exposed adults

While interest in the potentially salutary effects of positive well-being on cardiovascular health is increasing, we know relatively little about how positive states of mind affect cognitive and cardiovascular responses to stress in trauma survivors. We conducted a laboratory-based study with 84 adult trauma survivors to test the following hypotheses: (1) Greater positive states of mind will be associated with higher challenge appraisal, lower threat appraisal, and higher heart rate variability (HRV), controlling for posttraumatic stress symptom (PTSS) severity; (2) higher challenge appraisal and lower threat appraisal will mediate the association between greater positive states of mind and higher HRV, controlling for PTSS severity and body mass index (BMI). We conducted mediation analyses with 95 % confidence intervals and 5000 bootstrap samples to test threat and challenge appraisals as mediators of the relationships of positive states of mind with HRV responses to stress. Stronger appraisal of challenge mediated the effects of more positive states of mind on lower LF (nu) during recovery, controlling for PTSS and BMI. Threat appraisal was not a significant mediator of any association between positive states of mind and HRV reactivity or recovery. Our findings suggest that challenge appraisal may explain the association between greater positive states of mind and lower sympathetic arousal during recovery.