Discrepancy in HR statistics between watch and app
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Today I recorded a short interval workout with the Polar H10 on the Suunto Run. The HR graph on the watch seems to be correct, but the app shows something different. The last interval and the 3-minute cooldown are missing. But the time is correct
Note: Android App 6.0.2, Suunto Run Firmware 3.19.20
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Also using the H10 strap and having similar problems. What I think is happening here is that the heart rate recordings somehow get delayed / desynced in the app (and everywhere else, sports tracker, runalyze, strava, you name it). Yesterday, I was doing some hill sprints. I did the first hill sprint at roughly 26:12 into the run and the corresponding heart rate spike happens at 29:28. Later I did a sprint at 40:29 and the heart rate spike happens at 45:48. The gap is getting wider the longer the run is. When I stop the recording, the last X minutes of heart rate recordings are cut. When not using the strap, the HR spikes happen when they should, without delay.
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@Yves-Jenni Hi, it happened to me too, reported here
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@Tomi
Same here, we are talking about 1km of delay. Hope the will fix it -
Patch 3.20.22 massively improved the situation, but there’s still a gap between pace and HR that widens over time.
A run with strides with H10:
A run without the strap:
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@Tomi Yes, it seems to have been worked on in the last updates. I wanted to describe the problem in more detail, but then waited because of the update.
Nevertheless, I’ll post a clear summary of the previous issue here (because I had already compiled it so nicely
)
CrossTraining_2025-08-15T16_32_49.fit
(I could add more examples, including those with the SmartSensor. But since the problem appears different now, I’ll leave it at that.)
The new variant of the problem:
There is definitely still a problem. I doubt it’s the H10, as it also happened randomly with my Suunto SmartSensor. Today, however, it happened again with the H10:
Here’s a somewhat strange interval run . The heart rate curve suddenly shifts around the first marker and then at the end simply stops, while pace and watts continue to be recorded
(Android App 6.1.4 Suunto Run Firmware 3.20.22)
Running_2025-09-09T08_23_43-1.fit
I couldn’t reproduce the problem in my short intervals during indoor training. That also worked well today with the H10.
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@Yves-Jenni it works well for now, nothing like what’s happening to you. I also use both the H10 and (mainly) the Suunto Sensor.
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@Hari-Seldon Okay, interesting. But @Tomi, you still have the problem?
Again today, during two short training sessions. This time with the Suunto SmartSensor:
Running_2025-09-11T11_50_09.fit
and immediately afterward, another activity
TrailRunning_2025-09-11T12_28_51.fit
Something is definitely out of sync here. I’ll try the Polar Verity Sense next time, but I think it happens with any sensor. It’s happening more frequently now. Before last update, I had the discrepancies in maybe one out of every four training sessions; now, it’s happening in about two out of three.
Note:
I’ve also noticed that newly synced activities displayed incorrect or incomplete data in the app, but the problem was later resolved. Possibly a problem with the sync status.
One more note:
The error is also visible in Runalyze, which suggests that the fit file is corrupted.
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@Yves-Jenni
Okay, interesting. But @Tomi, you still have the problem?
I haven’t been using the strap recently since (to my knowledge) there has been no updates. Will try today to see if anything has changed.
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@Tomi said in Discrepancy in HR statistics between watch and app:
Will try today to see if anything has changed.
No changes, identical results to what I previously posted. HR delayed roughly by one minute after 36 minute run.
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@Tomi Thank you. I was able to bring this topic here to the support team’s attention. Hopefully, they’ll find the error soon.
One more note: Today I tried the Polar Verity Sense, but I couldn’t reproduce the issue in three activities (2x cycling, 1x walking). -
Today I had several activities in a row (Suunto SmartSensor):
- Cycling
- Swimming
- Cycling
- Running
- Cycling
Noticeably, the problem only occurred while running. Cycling and swimming were no problem
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Another day with multiple workouts (Polar H10):
- Walking (correct)
- Trailrunning (0:51 - deviation ~5 min)
- Hiking (1:40 - deviation ~15 min)
- Walking (correct)
Yesterday with the Polar Verity Sense:
- Walking (correct)
- Running (1:15 correct)
- Trailrunning (0:45 correct)
With the Polar Verity Sense it always seems to work. Whether the ZoneSense calculation has anything to do with it -
After the latest update, I’ve also regularly noticed a strange discrepancy in the heart rate display on my watch.
Sometimes it freezes and only shows a much too high or low heart rate.
The graphs also show a delay or a completely unrealistic heart rate.
I’ve turned off zonence, but that doesn’t make any difference.
I have a Polar H10. -
@Jacobus said in Discrepancy in HR statistics between watch and app:
I’ve turned off zonence, but that doesn’t make any difference.
How do I turn off ZoneSense?
That also looks strange. What software are you using to display the data?
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@Yves_ A bit unclear on my part, I turned off the zonesense app.
This is a screenshot of Intervals.icu, by the way. -
@Jacobus ah, okay
I meant this because of the ZoneSense calculation. This is the only obvious difference between the results from the Suunto SmartSensor or the Polar H10 to the Polar Verity Sense. The optical Sensor doesn’t have that.
Although I still don’t understand what is depicted with it
