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Wrist OHR accuracy when not recording activity

jallamannen
over 5 years ago

I set out to try and figure out/prove that the OHR for me is very inaccurate when the FR945 is not actively recording an activity. I usually bike indoors and outdoors using a Edge 830 where I record the activity. With the TrueUp feature I get updated Training Status, VO2Max, Recovery Time etc on both my Edge 830 and FR945. But the Edge 830 does not support Intensity Minutes or Body Battery, so when I record a biking activity using Edge 830, the FR945 uses its OHR to update these metrics. The FR945 OHR in my case is reading way too low.

The first two tests proves that in my case, the FR945 OHR can be quite reliable, as long as the FR945 is actively recording.

Here is a 9 hour recording comparing the FR945 OHR during a day at the office with some walks. Comparing against a Wahoo Tickr Fit recorded on Edge 830. I'm satisfied with this result

Link to full analysis: https://analyze.dcrainmaker.com/#/public/2d3bb0a4-fed9-4cf4-643c-7615ff39bb70

Here is a 1 hour indoor bike ride recording comparing FR945 OHR vs a Garmin HRM-Dual recorded on Edge 830. Again very good results.

Link to full analysis: https://analyze.dcrainmaker.com/#/public/cea91f7e-270a-40d4-7fc4-4c5dda687ef5

Now, if the FR945 is not actively recording, that's when I have issues. Here is a 1 hour indoor ride, where the FR945 is set to broadcast HR and not recording any activity. I'm recording the broadcasted HR  on a Wahoo device and comparing against HRM-Dual recorded on Edge 830.

The first 20 minutes are just way off. The FR945 seems to think I'm resting. Eventually it seems to catch up, but then I did a hard sprint at minute 50, and the FR945 missed this completely. It even thinks my HR went down during the sprint.

Link to full analysis: https://analyze.dcrainmaker.com/#/public/be8daf1f-205c-4170-48b4-fa96e622a5db

It seems to me like the OHR on the FR945 is in some kind of low-power mode when the device is not actively recording, this makes me question all the features like Body Battery, Stress and Intensity minutes.
When the device is recording however, the OHR seems quite accurate.

  • 0 over 5 years ago

    Here is another indoor cycling activity. Again this shows the difference in "active" and "passive" mode. In this test I started with the FR945 OHR in broadcast mode, but not recording. The broadcast was recorded on a Elemnt device. Comparing vs a TickrFit recorded on a Edge 830.
    As you can see the same thing happens. In "passive" mode the FR945 does not pick up my elevated HR at all. The difference is a whopping 60bpm as some points. Then at approx min 23, I stopped the broadcast. I then started a Indoor cycling activity on the FR945, and set to broadcast during activity. This allowed me to still record the OHR on my Elemnt device. And as you can see from this point on, they match very good. Note, I had disabled all external HR monitors on the FR945. The blueish line is the TickrFit and the purple is the FR945 OHR.

    Full analysis: https://analyze.dcrainmaker.com/#/public/cd5e81e2-bcc9-44cf-7941-c565f4012541

  • 0 over 5 years ago in reply to jallamannen

    Just my two cents: I wore the watch for a whole day while recording a "Treadmill" activity. In practice I was doing what I do in my every day life - going to the office and working. The results were horrific. On the other hand, while recording a running activity and actually running - results were quite amazing.

  • 0 over 5 years ago in reply to talsela

    I've noticed likely "passive/active" OHR related influence on intensity minutes too:

    - 165 IM credited for 1:15 bike ride with 945's OHR @ 146BPM AVG

    - 202 IM for biking with 945 "passive" on my wrist, activity recorded using Edge 530 + Polar OH1, 3h total out of which 2h@169 BPM AVG race

    Time permitting I'll try to compare 945 broadcasting HR to my old VA3 vs Edge 530 + Polar OH1.

    Btw.  Garmin was asking for feedback on 2.64 OHR:

    forums.garmin.com/.../915953

    Did someone report this "passive/active" OHR matter to Garmin tech support? Implicates probably factory reset of device, HW replacement. Possibly multiple iterations, although it appears to be a software defect :-|

    Last but not least - I've noticed Move IQ was off on my device. Did someone experiment with Move IQ on?