The physiological cost of coping: a systematic review and meta-analysis on discrimination and heart rate variability

Abstract

Abstract Background Heart rate variability (HRV) reflects parasympathetic regulation and is typically associated with better health outcomes. However, minoritized populations, particularly African Americans, show a paradoxical pattern of higher resting HRV despite greater cardiovascular risk, a phenomenon known as the Cardiovascular Conundrum. Discrimination has been proposed as a key mechanism, but evidence remains fragmented. Methods The present meta-analysis quantified HRV in relation to discrimination across 3 domains: (1) resting HRV differences between minoritized and majority groups, (2) HRV reactivity to discrimination-related tasks, and (3) the association between perceived discrimination and resting HRV. A systematic search yielded 40 articles comprising 52 independent studies. Results Minoritized groups showed higher resting HRV than majority groups (g = .22, P < .001), as well as acute HRV reductions during discrimination-related tasks (g = −.17, P = .04), and lower resting HRV associated with greater perceived discrimination (g = −.19, P = .006). Evidence of publication bias emerged only for the latter meta-analysis. No significant moderators emerged to explain the substantial heterogeneity, with the exception of the type of HRV measure used. Conclusions These findings are consistent with the hypothesis that discrimination may become biologically embedded through acute vagal withdrawal during discriminatory events, a cumulative reduction in HRV associated with perceived discrimination, and a paradoxical elevation of resting HRV indicative of chronic compensatory regulation.