EnduroMetrics-HRV
· v1.1.11
About
EnduroMetrics-HRV
THREE HRV TOOLS. ONE DATA FIELD.
1 · A 3-minute HRV reading, any time you want one
2 · Live RMSSD while you move — before, during and after training
3 · HRV Recovery Kinetics — the time your RMSSD needs to climb back
to your resting baseline after a session
Everything is written into your .fit file and lands in Garmin Connect as real data you can compare week after week.
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YOUR RING MEASURES YOU ASLEEP.
YOUR WATCH MEASURES YOU MOVING.
Rings and overnight apps give you one number from hours ago, taken while you were completely still. It is a useful number. It is also a photograph of a body that was doing nothing.
Between waking up and lacing your shoes, your physiology has already moved, sleep, stress, heat, fuelling, yesterday's session.
EnduroMetrics-HRV measures you where the training decision actually gets made: standing up, walking, jogging, and recovering.
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TOOL 1 · INSTANT READING — 3 MINUTES, ANY TIME
Sit down, stay still, start the field. Three minutes later you have RMSSD, lnRMSSD, pNN50 and HR, the same HRV indices used in sports science research — saved permanently to your activity file.
Morning. Midday. After a stressful meeting. Before a race warm-up. Whenever you actually want the number, not just when you wake up.
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TOOL 2 · LIVE RMSSD UNDER LOAD
Most HRV tools go quiet the moment you start moving. This one doesn't.
Real-time RMSSD, expressed as a percentage of your own active baseline, with an R²-filtered slope so you see genuine drift instead of noise, plus AFI™ (Autonomic Fatigue Index) combining vagal withdrawal with cardiac load into one number.
Three signals, watched at once. One dropping is normal. All three converging is information.
Best used in Zone 1–2, where HRV still carries signal. Above Zone 2 HRV flattens out and the confidence indicator will tell you so.
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TOOL 3 · HRV RECOVERY KINETICS — THE ONE NOBODY ELSE GIVES YOU
Well-trained endurance athletes reactivate their parasympathetic system faster after hard efforts than untrained adults. The speed of that return is one of the clearest readouts of autonomic resilience there is.
(Dupuy et al., Eur J Appl Physiol 2021 — PMC8548865)
So measure it.
Before training: 3-minute seated baseline. Say it locks at 32 ms. Train as planned.
Afterwards: reopen the field, press LAP to keep your pre-session value as the reference, sit down, and watch RMSSD climb back.
The time it takes is your Recovery Window.
Faster than your usual → the session was dosed right.
Much slower than usual → it cost more than it felt like.
Same test, same conditions, every time. A number instead of a feeling.
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WHY ATHLETES KEEP IT ON THE WATCH
Readiness check before a key session · Recovery cost after it · Return between intervals · Rest control between strength sets · Trend tracking across a whole training block
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WHAT YOU NEED
An ANT+ chest strap that transmits RR intervals. Garmin HRM-Pro, HRM-Dual, HRM-Tri · Polar H10, H9 · Wahoo · Suunto · CYCPLUS H2 PRO
Wrist optical sensors do not transmit RR intervals accurately enough for beat-to-beat HRV. That is a physics problem, not a software one.
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For training and self-monitoring only. Not a medical device. Does not diagnose, treat, prevent or predict any condition. AFI™ and the ANS zone thresholds are EnduroMetrics' own analytics, not established physiological thresholds. Consult a healthcare professional before starting or intensifying exercise.
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- Website: https://endurometrics.com
- More: https://endurometrics.com/shop/garmin-data-field/endurometrics-hrv/
- Athletes Guide: https://endurometrics.com/endurometrics-hrv-for-athletes/
- UI Guide: https://endurometrics.com/endurometrics-hrv-ui-guide/
What's new
ATTENTION: The data field has been tested successful connectivity using the 1.Garmin HRM-Pro Plus, 2. Polar H10 (100% right connectivity) 3. CYCPLUS H2 PRO . The connection method is identical and works the same way with all compatible chest straps that support RR interval transmission.
If you experience any issue with a specific strap, please contact me via email and I will review it promptly.
Important: On your Garmin watch, make sure your chest strap is connected via BLE (not ANT+). This leaves the ANT+ channel available for the data field to read RR intervals correctly.
https://endurometrics.com/guide-endurometrics-hrv-chest-strap/
If the data field does not connect the first time, remove the battery from your chest strap for 5–10 seconds, reinsert it, and start the activity again. The connection should then establish normally.
Version 1.1.11
Cycplus H2 Pro is now fully compatible (requires firmware 1.1.0 or newer). To update your H2 Pro, please open the official CYCPLUS app on your phone, connect your strap, and install the available firmware update.
EnduroMetrics-HRV now officially supports the following chest straps (native RR interval / HRV support):
Garmin, Polar, Suunto, Wahoo, and Cycplus H2 Pro (with firmware 1.1.0+).
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v1.1.9 - Fixed bug that prevented bradycardic athletes from completing baseline collection.
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Version 1.1.7
ANT+ device tracking. FIX write conflicts
Baseline summary FIT fields: Adding Summary review in the end of workout with BL RMSSD, BL HR, BL lnRMSSD, BL pNN50
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Version 1.1.5
-HR Zone Indicator — Fixed positioning to move proportionally within each zone
-ANS Zone Indicator — Corrected movement logic so that 100% of baseline is at the center of the green zone, with higher values moving left and lower values moving right
-Timer Pause/Resume — Timer now stops completely when paused and resumes from the exact same point
-Black Background and draw lines Support — HR and ANS zone indicators and draw lines now switch to white color when black background is detected, ensuring visibility in both light and dark themes.
-AFI Zones updated to: 0-25 Green (Normal), 25-40 Yellow (Mild Fatigue), 40-60 Orange (Moderate Fatigue), ≥60 Red (Severe Fatigue) for improved sensitivity and clinical relevance.