Supplementary Material for: Yoga Nidra and Pain: A Between-, Within-Group Meta-Analysis and Dose response Meta-regression

Background: Pain, both acute and chronic, places a substantial burden on global healthcare systems. While conventional treatments may be limited in efficacy due to side effects, risk of dependency, or variable individual response, there is growing interest in mind-body complementary approaches. Yoga Nidra (YGN) has emerged as a promising non-invasive intervention for pain management. However, a clear understanding of its efficacy remains limited. This systematic review and meta-analysis evaluated the effects of YGN on pain outcomes. Methods: A literature search was conducted across seven databases and one trial database. Eligible studies included quantitative designs assessing the effects of YGN on pain. Methodological quality was evaluated using the Cochrane Risk of Bias tool for randomized controlled trials and the modified Downs and Black checklist for non-randomized studies. Random-effects meta-analyses were performed to estimate pooled effect sizes. Results: Twelve studies, comprising 1,176 participants, were included. Between-group analyses revealed that YGN significantly reduced pain compared to passive comparators (Hedge’s g: -2.05, p=0.01), while comparisons with active comparators (g: -0.31, p= 0.53) showed no statistically significant differences. Within-group analyses indicated significant pain reduction following YGN (g: -2.01, p<0.001). Subgroup comparisons of single versus multiple training sessions, as well as meta-regression analyses, revealed no significant dose-response relationship across intervention durations. Conclusion: YGN shows potential in reducing pain intensity compared to passive control conditions, with notable within-group improvements following intervention. However, given the low methodological quality across the included studies, these effects should be interpreted cautiously, as the observed effects may represent inflated estimates. Despite these limitations, YGN demonstrates potential as a complementary approach for pain management, underscoring the need for high-quality, standardized research to establish its efficacy as a viable clinical intervention.