Why are HRV metrics log-transformed before calculating z-scores?

Raw rMSSD and SDNN data follow a skewed, log-normal distribution. Applying a natural logarithm (ln) normalizes the distribution so z-scores reflect accurate statistical deviations.

What does a baseline coefficient of variation (CV) above 15% indicate?

A CV over 15% signals excessive baseline noise from inconsistent measurement protocol or lifestyle factors, indicating single-day shifts should be interpreted with caution.

What does the amber readiness tier indicate for training?

Scores between 40 and 69 place you in the amber tier, which recommends capping workout intensity at aerobic tempo or steady threshold work instead of maximum VO2max efforts.

Is an RHR baseline required to generate a readiness score?

No. The RHR baseline is optional; if omitted, the model automatically renormalizes the weighting across HRV, sleep hours, and prior session RPE.

What is the smallest worthwhile change (SWC) threshold used by the tool?

A change of |z| ≥ 0.5 standard deviations from your rolling baseline mean is flagged as a physiologically meaningful shift beyond typical daily noise.

Elysia Tools

Navigation

Fitness

HRV-Based Recovery & Readiness Score

Scores today’s recovery 0-100 from morning HRV (rMSSD/SDNN) and resting heart rate z-scores against your own rolling baseline, blended with last night’s sleep and yesterday’s session RPE — with a green/amber/red tier, meaningful-change (0.5 SD) detection, baseline noise (CV) check, and an intensity-ceiling training recommendation.

Details

What this tool helps you do

Enter this morning’s HRV and resting HR plus your last 7+ mornings of HRV baseline (one value per line; an RHR baseline is optional but adds the RHR z-score). rMSSD/SDNN are log-normal, so z-scores are computed on ln-transformed values — the same convention used by guided-training research (Plews/Laursen). A |z| ≥ 0.5 change counts as meaningful (smallest worthwhile change); baseline CV > 15% is flagged as too noisy to interpret; RHR +5 bpm over baseline triggers a fatigue/illness watch. The blend weights are HRV 30% / RHR 25% / sleep 30% / yesterday’s load 15% (renormalized without RHR data), following published readiness-score architectures. Tiers: ≥70 green (full session OK), 40-69 amber (cap at tempo/threshold), <40 red (recovery or rest). Not a medical device.

Execution

Run this tool

Fill in the form, run the tool, and review the result in one place.

Samples

HRV-Based Recovery & Readiness Score

What this tool helps you do

Run this tool

Examples that match this tool

Continue with connected tools and hubs

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Post-Hard Session Fatigue Check

2. Post-Rest Day Readiness Confirmation

FAQ

Contentful Cloud-based CMS Samples

Web Image Processing Python Samples

Android Image Processing Java Samples

Android Image Processing Kotlin Samples

AsciiMath LaTeX MathML Equation Converter

ECharts Theme Token Extractor

ESA PB05-Style Brouwer–Lyddane Averaged-Element Orbit Propagator (J2–J6 + Luni-solar)

Image Palette to Design Tokens