Garmin HRM Pro Dropout

I’m using Zwift on a Windows 10 laptop. I recently bought a new Garmin HRM Pro as it has the BTE to transmit and record on Zwift; also using a Kickr Core.

I am regularly seeing the HRM dopout without warning and I lose any HRM recording - no warning or pattern noticed. The HRM is working fine as it also pairs with my Garmin 920XT and there are no recording issues between these devices. The HRM Pro is discoverable on the laptop as a BTE enabled device and everytime I login to Zwift, it pairs and begins recording but then drops out during the rides.

Anyone experienced anything similar, or any ideas? Thanks.


I would suggest using ANT+ over Bluetooth.

@Paul_Allen: I wonder… why would you recommend ANT+ over BLE?

@Trevor_Batey_SMART12: I experience the odd BLE disconnect as well… Does your Kickr disconnect as well (at the same time)?

Yes, om occassion the Kickr doesn’t pick up the BLE at the start but it doesn’t drop out

On occasion, both my HRM and trainer get dropped - simultaneously, mid-ride, sometimes multiple times in a single session.

After a short while, I am able to reconnect and proceed as if nothing happened.

No idea why… (I’ve opened a ticket with Zwift support - will update if/when progress is made)

I started to have the same issue, only with zwift and hrm pro band from garmin. But everthing Works smoothly in the garmin gps.

Any tip or Idea why? Thanks

Welcome, José!

Sorry, no idea yet.

Just to clarify: “same issue” as in “everything disconnects” or “only my HRM disconnects”?


Zwift got back to me and directed me to the troubleshooting guide. Here it says dropout of BLE is likely to come from EM interference across the transmission range and that can be generated by things such as fans, bluetooth speakers or power cables to computers.

These shouldn’t be used!!! Not exactly helpful

The thing is this dropout doesn’t occur between my HRM Pro and head unit - just between the HRM Pro and Zwift?

I’m going to ask the question of Garmin Help

BT is a frequency-hopping protocol. This means it will find and use those bands where there is the least amount of interference.

No need to shutdown everything (unless your have a wide-band 2.4Ghz noise-generator that covers everything in the relevant ISM band…)

Most Bluetooth devices are a 1 to 1 connection so most likely your HRM is connecting to your head unit via ANT+ so that’s why it doesn’t drop out like Zwift. As others have said above I’d recommend an ANT+ dongle and usb extension cable for your computer.

Been using that combo myself since switching from AppleTV to a Windows 10 PC a year ago and haven’t had any drop out issues. YMMV.

i would suggest taking the Garmin head unit out of the equation. Or put everything on ANT+ but mixing ant+ and Bluetooth can cause dropouts.

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Thanks for the idea and I’ll experiment with this. I’ve bought an ANT+ dongle and did try using it for the HRM whilst running the Kickr on BLE but the RPM on the Kickr was going crazy and fluctuating all over the place, so suspect it doesn’t like the mix.

Thanks for the idea, I’ll try that. I did try the ANT+ and BLE mix but it cuased problems with the Kickr not reading RPM properly. The problem at the moment with using ANT+ for the Kickr is that I don’t have a speed/cadence sensor and I’d need one if using ANT+. Will play around and see where I get now I understand things a bit better. Cheers.

Thanks. I’ll work this into the other answers and like to think I know what you mean but my technological capabilities are limited and I usually need an explanation at ‘6-year old in crayon’ level :grinning:

HI, thanks for the reply.

I bought an ANT+ dongle and usb extension cable for your computer, and it solved all the power drops in my trainer!

But i still have issues with my Garmin HRM tri band, is having drops in zwift by ant+, but in my head unit is working fine like always!!

I will try to disconnect the garmin HRM tri to my head unit next time…

I have this exact problem - only the HRM PRO-PC BLE connection dropping out. Everything else fine. Did anyone verify if it is the ant+ and BLE connections running simultaneously that causes the issue?


Unless another device is trying to connect to your HRM, based on my experience, Zwift has a bug causing HRM BLE devices to periodically disconnect (and re-connect, and again…)

Not acknowledged by Zwift, but definitely so by my experience.

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I started another thread with a similar problem on a BLE Peloton branded HRM. I don’t know who they are using for the electronics. I cannot use the HRM at all, it acts like it picks up the device then constant “no signal.” It works on a Windows 10 laptop, but not two desktops. Extensive troubleshooting details in there.

Zwift support was equally unhelpful. The only thing even sort of technical they wanted me to try was taking the bluetooth dll’s from the working machine to a non working machine, but I have not tried that yet.

I am having this issue starting today. My HRM pro was connected and fine. Then it said no signal. I tried to reconnect it and then it removed it couldn’t find it at all.

I haven’t found any good solution yet.