Meaning in life and vagally-mediated heart rate variability: Evidence of a quadratic relationship at baseline and vagal reactivity differences.

Higher meaning in life (MIL) consistently predicts better health, but the physiological processes underlying this relationship are not well understood. This study examined the relationship between MIL and vagally-mediated heart rate variability (VmHRV) under resting (N = 77), stressor (n = 73), and mindfulness intervention (n = 72) conditions. Regression was used for MIL-VmHRV analyses at baseline, and longitudinal mixed models were used to examine phasic changes in VmHRV as a function of MIL. Regression revealed a quadratic MIL-VmHRV relationship, and mixed models linked higher MIL to greater stress-reactivity but not enhanced stress-attenuation. MIL and mindfulness did not interact to influence VmHRV recovery after experimental stress. Findings suggest that cardiac vagal tone and cardiac vagal reactivity are linked to MIL, shedding light on the physiology underlying MIL and its health associations.