How to - use Garmin watch (forerunner 645) and broadcast heart rate data to Zwift

This is not a question or a request for support. Actually this is a how to.
I’ve had previously a discussion with Zwift support and also on other forums, but didn’t received any clear answers.
So, it might be that this could be helpful for other people with Garmin watches that would like to use it for heart rate data on Zwift instead of purchasing chest strap.

Steps on how to broadcast heart rate data to Zwift from Garmin watch (in my case Forerunner 645).
Equipment used:

  1. Win 10
  2. Garmin Forerunner 645
  3. USB Ant +/Bluetooth adapter (took the cheapest one: ANT+ USB Stick Adapter (Amazon Canada link) *
    * this specific usb adapter comming without official support, but you could take drivers and installation manual from trainerroad page (link to manual and download)


  1. Once usb adapter is attached and drivers are installed, go to Garmin Forerunner 645 watch:

Choice 1
Settings --> Wrist Heart Rate --> Broadcast Heart Rate
In this case the watch will start broadcasting the Heart Rate and now you can go back to Zwift and press on Search under Heart Rate devices. It should find it easily.
In this configuration you will not be able to use the Forerunner 645 watch since the screen will be “locked” on the broadcasting data of the heart rate.

Choice 2
Settings --> Wrist Heart Rate --> Broadcast During Activity (make it ON)
In this case when starting a new activity (example: indoor cycling) the watch will start broadcasting the heart rate, so just go to Zwift, press Search under Heart Rate devices.

1. Choice 2 – if someone could confirm to me if he could use the watch during the activity when it broadcasting the heart rate. Fore example : changing between screens, apps etc…

2. It could be a good idea to create a proper How to and add it to Zwift support page. Let me know if you’ll need any help with it )

well, that’s all for the moment )

Vivoactive 3 broadcasting heart rate data to Zwift - probably will work also, at least by the logic of official Garmin support page it should broadcast outside (Vivoactive 3 heart rate broadcast)
–but should be tested.

I can confirm this works for the Vivoactive 3 (Music) as well. This broadcast function was my main motivator to buy it.
Now only if I could get the integrated HR-sensor to consistently pick up my HR and not lock onto something close to my cadence consistently…


Yep, it works fine on my Vivosmart HR+ as well.


Ok. So, finally made my first ride at Zwift and here what I can confirm:

With the configuration of Choice 2 (Broadcast during activity), I could actually see the activity (indoor cycling) on the Garmin Forerunner 645 screen, can go through the details of the activity during the ride and in the same time Garmin watch is broadcasting the heart rate data to Zwift through usb Ant+/Bluetooth adapter to Win10 machine.
* - found that after the activity I have two dublicate activity results on Garmin Connect app: same activity, but with one result from Garmin Forerunner 645 and another from Zwift. But this one is totally different case to solve ).

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You need to ensure IQ is enabled on Garmin so it can see its the same activity thats been logged twice.


Yes, tried this one and over more then a month always having duplicate activities.
…have some hypothesis about why am I receiving two duplicate activities: it might be that Garmin IQ feature will recognise two data activities as one unique only in case if the X time difference (start and beginning time) is not bigger then Y minutes (not sure how big the difference should be). In my case I am always starting the watch earlier then Zwift and always forgetting to turn in off immediately after the activity. But still, this is just a hypothesis.

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I don’t see where to set ‘broadcast’ in mine, what did you do?

On my HR+ You scroll to the HR screen and then press and hold it until a message with a tick box appears asking if you want to broadcast HR.

Hi, Eric.
Here for Forerunner 645 / 645 music :

Same logic for Vivoactive 3.

If I use the Garmin watch with a chest strap ( 735xt ). Should I pair the chest strap to Zwift or better the watch?
I have connected zwift to Garmin connect.
Does anybody know if wearing the watch during the zwift training causes double data at Garmin connect? As we get the data from zwift + the recordings of the watch?

Thanks for these instructions.

Any ideas on broadcasting HR from Garmin watch with Zwift on iPad? I tried doing it but zwift on iPad is not picking up the HR.

Anyone have success with broadcasting HR from their Garmin watch to Zwift on iPad?

I could be wrong, but iPad is not accepting any Ant+ broadcast.
So you’ll need some adaptor that will bridge HR from Ant+ to Ble or some device that will accept Ant+ under the iPad or just heart rate monitor strap like Garmin HRM-Dual or 4iii HRM (also Ant+/Ble bridge).

Hi, My Fenix 6 (and the Kickr) will connect to my Microsoft Surface through Bluetooth without an Ant+ Adaptor. Is not just connecting through Bluetooth not recommended because it limits functionality or are these instructions for devices not bluetooth enabled?


@Terri_Aitken - I’ve found ant+ to be more stable/smoother than bluetooth (found Bluetooth to be a bit laggy with power etc read outs on zwift). I got a cheap dongle off Amazon.

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this works on my Garmin Instinct.