Heart Resonance reads heart rate over Bluetooth Low Energy (BLE). Most dedicated chest straps do this natively. GPS watches usually can, with a setting change. Apple Watch cannot — but a free third-party app fixes that. Here's what you need to know for your device.
How it works
The app connects to any device that broadcasts the standard Bluetooth Heart Rate Profile (HRP). This is an open standard — the same protocol a gym treadmill uses to pick up your chest strap. When a device advertises itself over BLE using this profile, Heart Resonance can see it and connect.
The important distinction is between wearing a heart rate sensor and broadcasting it. Almost every fitness device measures your heart rate. Far fewer broadcast it continuously as a BLE peripheral. That broadcast step is what the app needs.
Dedicated chest straps send individual beat-to-beat RR intervals — the gold standard for HRV and resonance scoring. GPS watches and optical sensors typically send only BPM (a rolling average), which the app still uses for all coherence analysis and resonance frequency detection. Both work. Chest straps just give you richer data.
Category 1: Dedicated chest straps — just pair it
If you own a dedicated chest strap from any of the major brands, it almost certainly broadcasts BLE HRM natively. Wet the electrodes, strap it on, open Heart Resonance, and tap the Bluetooth button. The device will appear in the scan list within a few seconds.
Devices in this category include:
- Polar H10, H9 — the gold standard for RR interval accuracy. Pairs instantly.
- Garmin HRM-Dual, HRM-Pro, HRM-Pro Plus — dual ANT+/BLE; the BLE side pairs with the app.
- Wahoo TICKR, TICKR X, TICKR Fit — all broadcast BLE HRM natively.
- Scosche Rhythm+ 24, Rhythm Wave — optical arm bands that broadcast BLE.
- CooSpo, Magene, Powr Labs and most generic BLE chest straps.
You do not need to do anything in the device's own app first. The strap broadcasts automatically when powered on and worn.
Category 2: Garmin GPS watches — enable BLE broadcast in settings
Most Garmin GPS watches (Fenix, Forerunner, Vivoactive, Venu, Epix series) can broadcast their wrist heart rate over BLE. This feature is off by default because it drains battery faster and the watch's primary BLE link is usually to your phone.
To enable it:
- On the watch, go to Settings → Heart Rate → Broadcast Heart Rate.
- Toggle it on. The watch will now advertise as a BLE HRM device.
- Open Heart Resonance and scan for devices. Your watch will appear.
On some Garmin models the setting is called Broadcast Heart Rate and appears as a widget or a menu item within an activity rather than in the main settings. If you can't find it, check the watch's manual or search "broadcast heart rate" in Garmin Connect IQ — there are also free data fields that enable this.
The Garmin wrist optical sensor sends BPM only — no RR intervals. The app works perfectly, but for the richest HRV data, pair a Garmin HRM-Pro chest strap alongside the watch (or instead of it). The HRM-Pro broadcasts BLE independently of the watch.
Category 3: Polar GPS watches — built-in BLE broadcast
Polar Vantage V2, Vantage M2, Grit X Pro, Ignite 3, Pacer Pro, and most other recent Polar watches support BLE heart rate broadcasting natively.
- On the watch, go to Settings → Heart Rate → Broadcast HR.
- Enable it. The watch begins broadcasting immediately.
- Scan in Heart Resonance. The watch appears as a BLE HRM.
Older Polar watches (M430, A370) may not have this feature. Check your model's specifications at polar.com.
Category 4: Suunto and Coros GPS watches
Several Suunto models — including the Race, Vertical, 9 Peak Pro, and Suunto 5 Peak — support BLE heart rate broadcast. Look for HR Broadcast or BLE Broadcast in the watch's sensor or connectivity settings.
Coros watches (Pace 3, Apex 2 Pro, Vertix 2S) also support BLE HR broadcast, typically found under Settings → Sensors → HR Broadcast.
Category 5: Apple Watch — needs a third-party app
Apple Watch does not natively broadcast heart rate as a BLE HRM peripheral. Apple's design keeps Bluetooth tightly controlled — the watch advertises only to iPhones running Apple-approved protocols, not to arbitrary BLE centrals like Heart Resonance.
The workaround is a watch app that reads the heart rate sensor and re-broadcasts it as a standard BLE HRM. Several exist on the App Store:
Recommended: Wristly Heart Rate Monitor
Wristly is the most widely used solution for this purpose. Install the app on your Apple Watch, launch it, and it immediately starts broadcasting your heart rate as a BLE HRM peripheral. Heart Resonance will see it in the device scan.
- Search "Wristly Heart Rate Monitor" in the App Store and install it (free).
- Open Wristly on your Apple Watch.
- Leave Wristly running in the foreground during your session — watchOS may throttle background sensor access.
- Open Heart Resonance on your iPhone and scan. "Wristly" or "Apple Watch" will appear.
Alternative: WorkOutDoors
WorkOutDoors is a full-featured workout app for Apple Watch that can broadcast heart rate over BLE as a side effect of recording an activity. If you already use it for outdoor activities, start a workout in WorkOutDoors and then connect Heart Resonance to it. The broadcast is active while the workout runs.
A note on accuracy
Apple Watch uses a wrist-based optical sensor, which gives you BPM readings — not individual beat-to-beat RR intervals. The app works with this and can still run the full resonance frequency assessment and coherence scoring. If you want the richest possible data (individual RR intervals for HRV), pair a chest strap instead. Many users with Apple Watches keep a Polar H10 or Garmin HRM-Pro specifically for coherence sessions.
Category 6: Samsung Galaxy Watch and Wear OS
Some Samsung Galaxy Watch models and Wear OS watches support BLE heart rate broadcast through their native settings or through apps. The availability and path vary significantly by model and software version.
- Samsung Galaxy Watch 6, 7, Ultra — check Settings → Health → Measurement for a BLE broadcast option. Alternatively, search the Galaxy Store for "HRM broadcast" apps.
- Wear OS (Google Pixel Watch, Mobvoi TicWatch) — third-party apps like HRM for Wear from the Play Store can broadcast BLE heart rate.
If your Galaxy Watch or Wear OS device doesn't have a native broadcast option, search your device's app store for "BLE heart rate broadcast" — several utility apps fill this gap.
Category 7: ANT+-only devices — you need a bridge or an upgrade
Older heart rate monitors — certain legacy Garmin HRM straps, early Wahoo sensors, some older Polar straps — broadcast only over ANT+. ANT+ is not the same as Bluetooth Low Energy, and smartphones do not have ANT+ radios.
Your options are:
- Upgrade to a dual-band device. Every major brand now sells straps that broadcast both ANT+ and BLE simultaneously (Garmin HRM-Dual, Wahoo TICKR, Polar H10). This is the simplest fix.
- Use an ANT+ to BLE bridge. The NPE CABLE device plugs into an ANT+ sensor and re-broadcasts it as BLE. It works, but adds cost and something else to charge.
To tell if your existing strap is ANT+-only: check the packaging or manual for the BLE or Bluetooth logo. If it lists only ANT+, it won't connect directly.
Quick reference
| Device type | What to do | Data quality |
|---|---|---|
| Polar H10 / H9 | Just pair — broadcasts natively | Excellent (RR intervals) |
| Garmin HRM-Dual / HRM-Pro | Just pair — broadcasts natively | Excellent (RR intervals) |
| Wahoo TICKR / TICKR X | Just pair — broadcasts natively | Excellent (RR intervals) |
| Garmin GPS watch | Enable "Broadcast Heart Rate" in Settings | Good (BPM only) |
| Polar GPS watch | Enable "Broadcast HR" in Settings | Good (BPM only) |
| Suunto / Coros watch | Enable "HR Broadcast" in Settings | Good (BPM only) |
| Apple Watch | Install Wristly (App Store), run during session | Good (BPM only) |
| Samsung Galaxy Watch | Check settings or install Galaxy Store app | Good (BPM only) |
| ANT+-only strap | Upgrade to dual-band, or use NPE CABLE bridge | N/A (won't connect directly) |
Troubleshooting
The device doesn't appear in the scan. Make sure it is actively broadcasting (chest straps need contact with skin; watches need broadcast mode enabled). Check that your phone's Bluetooth is on and you've granted the app Bluetooth permission. On Android 12+, location permission may also be required for BLE scanning — the app will prompt you.
The device appears but won't connect. Your device may be connected to another app or phone. Disconnect it from the other device first. Some straps only allow one BLE connection at a time.
It connects then drops. Keep your phone close (within 2 metres) during sessions. Thick walls, microwaves, and 2.4 GHz Wi-Fi can interfere with BLE. Move away from obvious sources of interference.
Apple Watch keeps disconnecting. Wristly must stay in the foreground. watchOS aggressively suspends background apps. Keep the watch screen on or set it to wake on wrist raise during your session.