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HR Broadcast Coming soon
HR Broadcast app icon For Apple Watch

Your Apple Watch is the heart-rate strap.

HR Broadcast turns Apple Watch into a standard Bluetooth heart-rate sensor. Zwift, gym equipment and bike computers pair with the watch itself, just like a chest strap. Nothing runs on your iPhone.

watchOS 26 or laterHealth and fitnessComing soon
HRB 9:41 142 BPM · ZONE 3 Broadcasting · 2
How it works

Start, pair, ride.

If it pairs with a Bluetooth chest strap, it pairs with your watch.

1

Start on your watch

Pick Ride, Run or Other. Your watch starts advertising as “HRB”.

2

Pair it like a strap

In Zwift, on the treadmill or on your bike computer, choose HRB from the heart-rate sensors.

3

Train

Heart rate streams every second. Your iPhone stays free: Zwift can even run on the same phone.

Works with

Anything that takes a chest strap.

HR Broadcast speaks the standard Bluetooth heart-rate profile, so there's nothing to install on the other side. On runs, it's a footpod too, sending speed and cadence.

Heart Rate 0x180DRunning Speed & Cadence 0x1814BatteryDevice Information
Zwifton iPhone, iPad, Mac or Apple TV
Gym treadmills and bikeswith Bluetooth heart rate
Bike computersthat pair with Bluetooth sensors
Other training appsanything that takes a chest strap
Features

Built for long sessions.

The details that keep the right number on screen an hour into a ride.

Broadcast
Stable pairingZwift stays paired between sessions. Data resumes the moment you press Start.
Honest dropoutsA late reading shows as Delayed. After 15 seconds, apps get “no contact” instead of a frozen number.
Multiple receiversZwift and the treadmill at the same time, if you like.
Keeps runningWrist down, screen off: it keeps broadcasting, and recovers if watchOS restarts it.
Run and ride
Footpod for runsSpeed and cadence from the watch. Indoors it learns your treadmill; outdoors it uses GPS.
Guided calibrationA hands-free ladder from your slowest walk to your fastest run, in 3 or 5 steps.
Auto-stop that asks firstOff the wrist, nothing connected or battery low? A 60-second countdown, then it stops.
Session reportUptime, heart rate, dropouts and packets sent. Save it to Health or discard it.
Workout mode

The Workout app's job, while you broadcast.

While HR Broadcast holds the workout, Apple's Workout app can't run. So we brought its job along.

Read your power meter, smart bike or treadmill. See up to four big numbers per screen and turn the Digital Crown for the next one. Mark laps with Double Tap, run work and rest intervals, and save everything to Health.

Power metersSmart bikesBluetooth treadmillsLaps and intervalsSaves to Health
RIDE · LAP 3 24:18 POWER 3S 248 W HEART RATE 151 bpm CADENCE 88 rpm
Privacy

Your heart rate goes where you send it.

Readings travel from your wrist to the devices you pair, and into Apple Health only when you choose Save. Nowhere else.

Read the privacy policy
Switched off, for good
AccountYou never sign up or sign in.
Our serversThere aren't any. The app works without internet.
Ads and trackingNone, and no analytics either.
Questions

Good to know.

Do I need an iPhone app?

No. HR Broadcast runs on the watch. You need your iPhone only to install it, like any Apple Watch app.

Which Apple Watch do I need?

Any Apple Watch with watchOS 26 or later. Marking laps with Double Tap needs Series 9 or later.

Can Zwift run on the iPhone my watch is paired with?

Yes, that's one of the reasons HR Broadcast exists. Zwift may show your watch's own name instead of “HRB”. That's watchOS, and it works the same.

Why does it say “Delayed”?

watchOS sometimes delivers heart rate late. After 8 seconds we show Delayed; after 15 we tell paired apps there's no contact, so you see a gap instead of a wrong number.

Is HR Broadcast made by Apple or Zwift?

No. It's made by ButtonBench, an independent studio, and isn't affiliated with Apple or Zwift.

Leave the strap at home.

HR Broadcast is coming to the App Store for Apple Watch.

Coming soon on theApp Store