Abstract
This randomized controlled trial compared 4-week self-guided self-compassion meditation (SCM) and mindfulness meditation (MM) apps among workers in two active arms (n = 201); analyses included intervention initiators with session-level data (SCM n = 86; MM n = 85). Primary daily outcomes were pre-session levels and immediate pre–post changes in HR, heart rate variability by RMSSD, and subjective relaxation; secondary weekly outcomes were PANAS and Affect Grid scores. Repeated-measures ANOVA and linear mixed models examined time and group effects. Daily models showed increased pre–post RMSSD differences and pre-session HR across days in SCM, stronger pre–post HR reduction and increased pre-session HR in MM, and reduced pre–post relaxation differences in both groups, with no group × day interactions. Weekly LMM analyses suggested reduced negative affect in SCM; however, SCM and MM showed broadly comparable effects, with no significant group × time interactions across daily and weekly outcomes. These findings support the value of short-term trajectories and physiological markers and warrant longer follow-up.