The 5HRV Autonomic Pattern Score

Background: Five-minute heart rate variability (HRV) yields several partially overlapping indices. RMSSD is a comparatively robust marker of short-term vagally mediated variability, whereas the LF/HF ratio describes a relative spectral pattern but is not a direct measure of cardiac sympathetic tone or sympathovagal balance. Interpretation is further complicated by strong age- and sex-related differences in population distributions. Objective: To specify the 5HRV Autonomic Pattern Score, a transparent deterministic method that combines age- and sex-adjusted RMSSD and LF/HF reference placement into a directional summary while retaining the separate reporting of vagal modulation, relative spectral pattern, and total short-term variability. Methods: Published P5, P25, P50, P75, and P95 reference values from the 6,891-participant Danish Study of Functional Disorders (DanFunD) were used for adults aged 18-72 years. The RMSSD was mapped to a continuous percentile using piecewise linear interpolation. LF/HF was mapped by piecewise interpolation on a logarithmic scale and capped at P5-P95 for scoring. The percentiles were transformed into standard normal deviates. A vagal direction deviation was defined as a negative RMSSD z-score and a spectral direction deviation as an LF/HF z-score. The weighted composite is 0.70 times the vagal deviation plus 0.30 times the spectral deviation and is normalized to a -100 to +100 score using 1.645, the one-sided standard-normal P95 magnitude. A separate concordance category prevents opposing or non-central component patterns from being presented as ordinary balance. Conclusions: The 5HRV score is an evidence-informed, reproducible pattern index that is not a direct measurement of sympathetic nerve activity or a validated diagnostic classifier. Its principal purpose is to make five-minute HRV interpretation more consistent and clinically readable, while preserving the underlying component results.