rRR
Median Relative Rr Interval Distance
| Aliases | rRR |
| Domain | time, statistics |
| Distribution family | Gamma |
| Equation | median(euclidean_dist(relRR; mean(relRR)))*100 |
| Resource intensity | ◍◍◌◌◌ low, Level 1–2 (base statistics over successive differences). (measured, see §Resources) |
Definition
Median relative RR interval distance. Formally: median(euclidean_dist(relRR; mean(relRR)))*100.
What does normal look like?
Fitted normative prior: Gamma(α = 4.165, θ = 0.8806), KS p = 3.5e-172, n = 61715.
Empirical distribution over the pooled nsrdb+nsr2db normative windows (360-beat windows, 120-beat stride), overlaid with the fitted Gamma prior density. Vertical lines mark the median and the 5–95% range.
Normal-range summary (pooled nsrdb+nsr2db)
| statistic | value |
|---|---|
| median | 3.05 |
| IQR (25–75%) | 2.424 – 4.05 |
| 5–95% range | 1.806 – 6.734 |
| mean ± sd | 3.667 ± 3.108 |
| n windows | 61715 |
n varies by feature only through per-window validity over the full pooled nsrdb+nsr2db table (n up to 61 715; e.g. sampen/mse drop windows where the statistic is undefined). ulf is the one exception: a 360-beat (~5 min) window contains no ULF-band power, so it uses a long-window NSRDB-only extraction (see its own page).
Use cases
- Artifact-robust HRV summary from relative RR intervals (Vollmer 2015).
- Field / wearable recordings with occasional ectopy or noise.
- Complements SDNN/RMSSD when data quality is uncertain.
Applications by area
Evidence is reported at the measure-family level; a specific variant may not be the exact index measured in every cited study.
No dedicated applications literature was harvested for rRR; treat its application evidence as sparse until a dedicated search is done. Its aliases and closest relatives may have their own applications; see the HRV Variable Zoo overview.
See the effect-distribution meta-analysis page for the harvested per-study effect sizes/p-values behind these domain summaries (docs/zoo_gen/effect_stats.csv).
Resources
Resource-intensity rank ◍◍◌◌◌ low is measured: median wall-clock time and allocations over a 360-beat window on synthetic realistic RR (docs/zoo_gen/bench_resources.jl; full grid in resource_bench.csv).
| metric (360-beat window) | value |
|---|---|
| cold median wall-time | 0.009818 ms |
| warm median wall-time | 0.009888 ms |
| allocations (cold) | 21.3 KiB |
Cold = fresh memoization caches (builds every shared representation from scratch); warm = shared representations (diff, periodogram, Poincaré coords, DFA fluctuation) already cached, so only this feature is recomputed. The tier is derived from the cold cost; see Level 1–2 (base statistics over successive differences).
Citation
Vollmer (2015): a robust, simple relative-RR measure of HRV.
Seminal reference(s): (Vollmer, 2015).
See the References page for the full bibliography.