Monitoring training adaptation: a scoping review of the relationship between self-reported subjective variables and resting vagally-mediated heart rate variability (vmHRV) in adult athletes

Purpose: Explore the relationship between vagally-mediated heart rate variability (vmHRV) and self-reported subjective variables (SVs) in adult athletes, and evaluate the methods used to measure these markers. It aims to provide evidence-based recommendations for athletic monitoring and future research. Method: Following the PRISMA-ScR framework, a systematic search of Web of Science, PubMed, PsychINFO and Sport Discus identified 9359 records. Additional backward and forward citation searches were conducted. Studies were included if they were peer-reviewed, in English, involved athletes, and examined vmHRV in correlation with SVs. Studies in clinical populations, animals, and reviews were excluded. Thirty-one studies met inclusion criteria. Methodological quality was assessed using the Joanna Briggs Institute (JBI) appraisal, and inter-rater consistency was evaluated with Cohen's Kappa. Results: SVs were grouped into fatigue-recovery indicators, psychological states, and sleep-related variables. Higher vmHRV often correlated with improved recovery, better sleep, and lower perceived stress, though results were inconsistent. Substantial methodological heterogeneity was also observed. Cohen’s Kappa indicated high agreement, and JBI no discrepancies. Conclusion: The relationship between vmHRV and SVs is complex, influenced by individual (e.g. training status) and methodological (e.g. timing, tools) factors. This review highlights the need for personalized, integrated athlete monitoring, and presents new guidelines for future research.