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Broadcast Heart Rate Changes Erratically and is Different from the Watch Display

9749510

Recently, I've been using the broadcast heart rate function on the watch to get heart rate readings for both Zwift and my Edge 540 bike computer. However, the broadcast heart rate will frequently stays at 71 bpm, then jump up close to the "real" heart rate before freezing for a few seconds, then drop back down to 71 bpm. While this is happening, the screen directly on the watch will continue to display a heart rate different from the one I can see broadcast which follows the normal expected shifts in heart rate based on my effort. This heart rate on the watch screen never freezes or drops down to 71 bpm.

I've included images of 2 heart rate graphs below with the first image being the erratic behavior and the second being from a normal ride before this issue began. Both are recorded using an HRM Pro Plus, the watch, and an Edge 540 bike computer. 

It is important to note that I'm pretty sure I've determined this is a watch issue because the same incorrect heart rate is displaying with 2 separate, unconnected devices (Zwift and the bike computer), and I have replicated the same behavior by removing the HRM and recording with just the wrist sensor.

I'm not sure what my next course of action is here. I've restarted all the devices in the chain multiple times to try and isolate the issue, but it continues. I am sometimes able to solve the problem by turning the broadcast off and on a dozen times and it will start behaving about 20 minutes into my workout, but this is very annoying. Any ideas or suggestions are appreciated.

  • 0

    Are you starting an activity or broadcasting the heart rate from the watch during the workout? Placing the watch in an activity mode will help with heart rate accuracy. 

  • 0 in reply to Garmin - SP

    I'm just broadcasting the heart rate from my watch during the workout. I understand what you're getting at with the activity mode, and I'll give that a try, but the problem does not seem to be with the accuracy of the heart rate as demonstrated by the readout on the watch screen itself; it's purely the broadcasting which has stopped working correctly after a year of unproblematic use.

  • 0 in reply to 9749510

    Hi, did you ever get to the bottom of this? I am also having the same problem. It used to work perfectly but the last couple of times I've been on zwift my heart rate seems to read anywhere between 69 and 71 on the connection screen but my watch can be reading something completely different. 

  • 0

    Hi, did you ever get to the bottom of this? I’m now having the same issue.

    The last couple of times on Zwift, my heart rate is showing around 69–71 bpm, but my Epix Gen 2 watch (which is broadcasting HR) is showing something completely different, like 110 - 180 bpm.

    Not sure how to fix this, any ideas?

  • 0 in reply to 1024620

    This answer isn't very good, unfortunately, but for me the broadcasting began behaving normally again a few days after making this post. I didn't do anything specific regarding updating my watch, phone, or computer. 

    I'm assuming you aren't using a chest strap heart rate monitor based on what you wrote (please correct me if this is wrong), but if this is true, is confirms what I suspected that the chest strap didn't have anything to do with the issue. I had a (seemingly) separate issue where my chest strap would no longer connect to my phone/watch, but this was corrected by changing the battery. Usually, I get a notification when the battery is low, but that didn't happen this time for whatever reason.

    The only thing I could think to suggest is taking a look at whether or not you can force your Zwift app to update on whatever platform you're using? For reference, I'm running Zwift on Windows. 

  • 0 in reply to 9749510

    So I use a Garmin chest strap HRM3 SS and pair it to my Garmin Epix gen 2 watch.

    I just used my watch yesterday on its own and it worked perfectly..... I will unpaid the strap and repair and see how it goes tomorrow. 

    I swapped out the chest strap battery a few weeks back, so I don't think that is the issue. 

    When i checked online it said turn all Bluetooth devices in the room thstcyou are not using. I use the bike in the gym, so I can't really ask everyone to switch their watches off. 

    I also checked for updates on Zwift and it seemed to be up to date. 

    As I said I will try again tomorrow.

    Thanks for getting back to me. 

  • 0 in reply to 1024620

    My $.05 is that I am having the issue too.  If I attempt to broadcast and turn broadcast one and off several times, eventually the watch figures it out and the proper heart rate is broadcast. But I am having the same exact issue as  when doing an indoor workout with Zwift.