I’ve tracked my own HRV with a Polar H10 for a long time. Most tools give a morning spot check or a watch’s overnight average, and I wanted every beat from the whole night, so I built an iOS app that records it.
It needs a Polar H10 or Verity Sense, because it reads the raw RR intervals over Bluetooth. It won’t work with other straps or a watch alone.
What it does with a night:
- Cleans ectopics and dropouts out of roughly 20,000 beats
- Finds a quiet, stable window in the sleep (about 400 beats, DFA a1 between 0.75 and 1.0, steady HR, low artifact rate)
- Computes ln(RMSSD) and DFA a1 on that window
- Scores it against up to 60 of your own nights
Most people here use a1 during exercise to find VT1. At rest overnight it’s much less settled, so the app reports it next to RMSSD, not instead of it. If you’ve looked at resting a1, I’d like to hear whether you think it adds anything.
The time-domain math is checked against PhysioNet reference recordings, and the source is public if you want to check the artifact handling or window selection: GitHub - chrissharp80/emuqu: Recovery measurement for iOS and watchOS from raw heart-beat intervals. Records all night from a Polar H10 or Verity Sense, stages sleep, scores recovery against your own baseline, tracks workouts and training load across ten sports, and answers questions from your data with an on-device or bring-your-own-key AI coach. Swift 6. · GitHub
It doesn’t connect to intervals.icu. It exports RR intervals and summaries as CSV, and workouts go to Apple Health. Would writing nightly HRV to your intervals.icu wellness data be useful to you?
It’s free for 30 days, then $9.99 once, no subscription. I have 20 codes for a free unlock for anyone with an H10 who’ll tell me what’s wrong with it. Reply here and I’ll DM you one.