Ritvo, Paul G.Dang, Kevin2021-11-152021-11-152021-072021-11-15http://hdl.handle.net/10315/38702Background. Higher meaning in life (MIL) consistently predicts better health, but the physiological processes underlying this relationship are not well understood. Additionally, while MIL is theoretically supported as a state variable, few studies have investigated its state-like variability. Method. 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. As a secondary question, this study investigated the modifiability of state MIL via experimental exposure. Regression was used for MIL-VmHRV analyses at baseline, and longitudinal mixed models were used to examine phasic changes in (a) VmHRV as a function of MIL and (b) state MIL. Results. Regression analyses revealed a quadratic baseline MIL-VmHRV relationship, and mixed models linked higher MIL to greater stress-reactivity but not enhanced stress-attenuation. MIL and MM did not interact to influence VmHRV recovery after experimental stress. State MIL was lower after stress relative to baseline, higher after intervention relative to stress, and higher after intervention relative to baseline. Conclusion. Findings suggest that cardiac vagal tone and cardiac vagal reactivity are linked to MIL, and that MIL fluctuates even within brief timeframes. Future research is needed to further clarify the physiology of MIL and the extent to which brief interventions can influence life meaning.Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Mental healthElectronic Thesis or Dissertation2021-11-15Meaning in lifeEudaimoniaPurpose in lifepsychological well-beingHheart rate variabilityHRVRMSSDHF-HRVCardiac vagal reactivityCardiac vagal toneStressStress reactivityStress recoverySelf-regulationAutonomic balanceAutonomic nervous systemParasympathetic nervous systemSympathetic nervous systemNeurovisceral integration modelPolyvagal theoryMindfulnessMeditationRelaxationQuadraticNon-linearMixed effects modelsLongitudinal mixed modelsState variablesMindfulness-to-meaning theoryHealth psychologyPsychophysiology