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Q: Heart rate data inconsistent over course of workout

Anyone else seen inconsistent heart rate data collected by the Watch Workout app, in that the sensor ranges from accurate (130 to 135 bpm) to inaccurate (60 to 85 bpm) within a single workout?


The data comes from the Health app (Health Data->Heart Rate->Show all Data) and was collected using 3 different Workouts to make sure the issue was not with a single type of workout. I first used the 'Other' workout for 25 minutes of warmup with weight machines, and the data collected seemed accurate (average bpm of 91 with a reasonable range for the type of exercise)


However, with a more strenuous exercise (that raised my heart rate consistently to the 130s verified by sensors on the gym equipment) using the 'Elliptical' and 'Indoor Walk' Workouts, the Watch sensors fluctuated between the 80s and a more accurate 130s without discernible reason.


For example, with the Elliptical Workout, the data readings showed a starting heart rate of 116 for 2 minutes (with many data readings in that time); then 3 minutes of readings between 59 and 62; then 2 minutes of 131 to 134; then 6 minutes of 83 to 86; then 3 minutes of 135 to 140. This was all recorded during the time the Elliptical machine was showing a consistent heart rate between 130 and 140.


To test another Watch Workout, I stopped the Elliptical Workout and started the Indoor Walk Workout, still using the elliptical machine, with the same results...1 minute of 135 to 138; 2 minutes of 78 to 83; 2 minutes of 133 to 135; 2 minutes of 98; 2 minutes of 131 to 137, and so on.


Of course, these inconsistencies reported both a false heart rate average and low calorie total for the 2 workouts.


BTW, the Watch was snug on my wrist, the sensor light was on, this issues occurred with both versions 1 and 1.0.1 of the Watch software, and while my arm was sweaty, no one seems to have reported any problems with sweat. I have restarted both my iPhone 6 and Watch without effect.

Apple Watch, Watch OS 1.0.1

Posted on May 22, 2015 10:28 AM

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Q: Heart rate data inconsistent over course of workout

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  • by Ron Goodman1,

    Ron Goodman1 Ron Goodman1 May 22, 2015 1:05 PM in response to itsolutionz
    Level 6 (8,663 points)
    Apple Watch
    May 22, 2015 1:05 PM in response to itsolutionz

    I've occasionally seen the displayed rate drop suddenly to half my actual rate while doing weight work. I haven't

    seen it during hard cardio though.

  • by clarson1,

    clarson1 clarson1 May 23, 2015 8:21 AM in response to itsolutionz
    Level 1 (0 points)
    May 23, 2015 8:21 AM in response to itsolutionz

    I've noticed the same thing while cycling.  During hard rides when my hear rate is 140+ the readings will suddenly drop to 72 for a period of minutes, and then pop back up to 140 or so. I'm wondering if this might have something to do with me raising my wrist to check my average speed, but I don't have enough data to know of sure.  Tomorrow I'll ride without checking the watch at all and see what happens.

     

    On today's 24 mile ride though, my average was 114 BPM.  That's too low.

     

    FYI - It also, at times, drops down into the 50's when I'm not working out.  Throughout my life, I've always had a high heart rate, about 82 BPM, so this doesn't make sense.

     

    By the way, it's fit very snugly on my wrist, and I have light skin.  It's cool in the mornings when I cycle, so I don't think its a perspiration issue.

     

    There's something wrong with the watch.

  • by clarson1,

    clarson1 clarson1 May 25, 2015 7:12 AM in response to clarson1
    Level 1 (0 points)
    May 25, 2015 7:12 AM in response to clarson1

    I went cycling again today to test my idea that the act of looking at the watch might cause the heart rate reading to fail.  It did appear to cause it.  My reading dropped from 145 BPM to 72 BPM roughly at the time I raised my wrist to look at the watch.  But, it happened a few other times during my ride when I didn't look at the watch, possibly because I repositioned my hands on the handle bars.

     

    My overall average during 24 miles was 135 BPM.  Better, but still not accurate.