Application of heart rate variability in clinical practice and research: A systematic review of recent years.

This systematic review aims to assess the current use of heart rate variability (HRV) analysis in clinical research, focusing on the diseases studied, the common indices used, and the physiological insights gained. A search was conducted in PubMed, articles published in recent years (2019-2025) in English or Spanish involving humans and pathophysiological interpretations were reviewed. After screening and verifying quality criteria, 99 articles were included in the review. HRV was most frequently applied in mental, behavioral, or neurodevelopmental disorders; diseases of the nervous system, and diseases of the circulatory system. Across studies, interpretations clustered around Treatment/Stimulus effects and Etiology/Mechanisms, with comparatively fewer works focused on Diagnostic/Screening or Severity/Staging. Approximately 58% of articles justified a targeted selection of HRV indices aligned with their clinical hypotheses, whereas the rest relied on batteries of indices. This review highlights the diverse use and interpretation of HRV across clinical contexts, pointing to a lack of standardized protocols. The heterogeneity of recording durations, maneuver use, and spectral units provided, together with under-reporting of nonlinear prerequisites, all limit cross-study comparability and clinical translation. We outline a tentative roadmap for clinically oriented HRV work that emphasizes, where appropriate, measurement standardization, analytic rigor and transparency, and clinical translation, ideally supported by preregistration, harmonized reporting, and open, validated resources. Future research should focus on developing standardized and updated guidelines for HRV analysis to improve its clinical utility and to encourage interdisciplinary collaboration in selecting and interpreting HRV indices based on research objectives and clinical hypotheses.