HRV-Longitudinal-Analyzer is an open-source scientific software application developed to support the organization, management, longitudinal analysis, and reporting of Heart Rate Variability (HRV) data obtained primarily from Kubios HRV software. The software has been designed to facilitate reproducible research workflows in sports science, exercise physiology, clinical research, and health sciences. It provides automated participant management, structured project organization, longitudinal monitoring of HRV measurements, scientific report generation, and standardized data processing. The application has been developed following open science principles and integrates version control through GitHub together with long-term preservation and DOI assignment via Zenodo. Each software release is archived to ensure reproducibility, traceability, and proper scientific citation. Main features include: Longitudinal HRV data management. Participant and project organization. Automated scientific workflow. Standardized folder structure. Validation and technical documentation modules. Scientific report generation. GitHub and Zenodo integration. Cross-platform architecture (Windows, macOS and Linux). The software is intended for researchers, sport scientists, clinicians, and students working with heart rate variability analysis in research and applied settings. Keywords: Heart Rate Variability (HRV), Kubios HRV, Sports Science, Exercise Physiology, Scientific Software, Open Science, Reproducible Research, Longitudinal Analysis, Python.