Music therapy and vagally mediated heart rate variability: a systematic review and narrative synthesis

Background: An increasing body of evidence supports the use of music therapy forimproving health and wellbeing. In parallel, there has also been a rising interest in the use ofbiomarkers to assess its impact. One such biomarker is vagally mediated heart rate variability(vm-HRV), which is a non-invasive measure of parasympathetic nervous system activity.However, the impact of music therapy on vm-HRV is currently unclear.Methods: A literature search was performed in December 2023/January 2024 and updated inMarch 2025. Data related to vm-HRV was extracted and risk of bias was evaluated. Anarrative synthesis was performed according to the Synthesis Without Meta-analysis (SWiM)guidelines with an effect direction plot.Results: Twenty-eight studies were included. There was large heterogeneity in studysamples, contexts, music therapy interventions, and HRV measurement methods. There wasalso a high risk of bias. The results indicated increased vm-HRV during music therapy. Therewas also an association between improved vm-HRV and other positive health outcomes inthese studies.Discussion: While current evidence indicates that there are potential positive effects of musictherapy on vm-HRV, more high-quality research, especially regarding HRV methodology,interpretation and reporting, is needed. A high risk of bias, small sample sizes andheterogeneity in all aspects of the studies prevents any clear conclusions based on the currentevidence.