FAQ & Support

FAQ updated 12/2025

Getting Started

HeartCast broadcasts your Apple Watch heart rate to fitness equipment like Peloton, Zwift, and bike computers via Bluetooth.

How it works:

  1. Your Apple Watch monitors your heart rate using HealthKit
  2. HeartCast on your iPhone receives the heart rate data
  3. Your iPhone broadcasts to your fitness equipment over Bluetooth

Quick Start:

  1. Open HeartCast on your iPhone and Apple Watch
  2. Press Start on the Watch to begin the workout
  3. Connect your fitness equipment to HeartCast (it will appear as "HeartCast" in their Bluetooth/Heart Rate settings)

HealthKit Permissions (Important!)

HeartCast requires HealthKit permissions to read your heart rate and save workouts. Missing permissions are the #1 cause of issues.

Permissions can be missed during initial setup, or new app updates may require additional permissions that weren't previously requested. If HeartCast isn't working as expected, checking permissions is always a good first step.

Required Permissions

HeartCast needs permission to:

  • Read: Heart Rate data
  • Write: Workouts (required to monitor heart rate during sessions)

How to Enable Permissions

iOS 17 and later:
Settings → Privacy & Security → Health → HeartCast → Enable all toggles, especially Workouts

iOS 16 and earlier / Apple Watch:
Settings → Health → Apps → HeartCast → Enable all toggles

Common Permission Issues #heartcastsupport

Symptom: Pressing Start briefly shows "Syncing Heart Rate" then returns to the Start screen.
Cause: Workout write permission wasn't granted during setup, or a new update requires permissions that weren't previously needed.
Fix: Enable the Workouts toggle in Health settings as described above.

Symptom: Watch shows "Please enable Workouts permission" error.
Cause: The Workouts permission wasn't granted or was missed during setup.
Fix: Go to Settings → Health → Apps → HeartCast and enable the Workouts toggle.

Important: HeartCast creates a workout session to access your heart rate data. This is required by Apple's HealthKit framework. You can choose whether to save or discard the workout data afterward (see Workout Saving Preferences).

Connect HeartCast with Fitness Equipment

Execute these steps before every session (takes 10-15 seconds):

  1. Open HeartCast on both devices
    Open HeartCast on your Watch and iPhone. Wait for them to sync (a few seconds).

  2. Press Start on your Watch
    This begins heart rate monitoring and enables Bluetooth broadcasting from your iPhone.

  3. Connect your fitness equipment
    Open Heart Rate Monitor settings on your fitness equipment (e.g., Peloton). Look for "HeartCast" in available devices and press connect.

Important:

  • HeartCast must remain open and visible on your iPhone during the initial connection. After connecting, you can let the iPhone sleep.
  • Do not pair HeartCast in your iPhone's Bluetooth settings. Connect through your fitness equipment's heart rate monitor settings instead.

Supported Fitness Equipment and Bike Computers

HeartCast uses the standard Bluetooth Heart Rate Service (0x180D), compatible with most fitness equipment. This list is community-verified:

Confirmed Working

  • Peloton Bike, Bike+, and Tread
  • Peloton App on iPad and Amazon Firestick
  • Zwift (on iPad, Apple TV, or computer)
  • ROUVY (confirmed by ROUVY support and users)
  • TrainerRoad (iPad)
  • Wahoo Fitness App (iPad)
  • TacX Smart Trainer Software (Mac/iPad)
  • Hammerhead Karoo 2 and Karoo 3
  • FulGaz App
  • Bryton Rider 450
  • Lezyne Macro GPS
  • NordicTrack iFit equipment (C2950 Treadmill, RW850 Rower)
  • Echelon Fit App (iPad only)
  • iGPSPORT bike computers (user reported, results may vary)

Not Supported / Limited Compatibility

  • Echelon Bikes with integrated tablet: Unsupported
  • Garmin Edge devices (830, 1030, others): Users report connection issues
  • Wahoo Elemnt Roam/Bolt: Mixed results. May work only when iPhone is unpaired from the bike computer, which limits other features.

Peloton Connection Tips

Standard Connection Process

HeartCast Setup:

  1. Open HeartCast on iPhone and Watch
  2. Press Start on the Watch
  3. Verify heart rate displays on both devices

Peloton Connection:

  1. Start a class on Peloton
  2. Tap the Heart Rate Monitor icon
  3. Select "HeartCast" from available devices
  4. Important: If Peloton prompts to "pair" with your iPhone, press Cancel. HeartCast connects automatically without pairing.
  5. Wait 10-15 seconds for heart rate to sync
  6. Once connected, your iPhone can sleep

Peloton Troubleshooting #heartcastsupport

HeartCast not appearing:

  • Ensure HeartCast is open and visible on your iPhone (not just running in background)
  • Force restart HeartCast on your Watch (see instructions)
  • Verify versions match on Watch and iPhone (see Version Sync)

Constant disconnections:

  • Unpair HeartCast from Peloton's Bluetooth settings (look for "HeartCast-xxxxx")
  • Unpair Peloton tablet from your iPhone's Bluetooth settings (look for "Peloton", "Ruby", or "Android Tablet")
  • Connect HeartCast before connecting Bluetooth audio devices

Peloton shows "not connected" but heart rate is visible:

  • This is a known Peloton display bug. If numbers match on iPhone and Peloton, the connection is working.

Complete Reset (last resort):

  • On your Peloton tablet: Device settings → Apps → Peloton → Storage → Clear Cache

Common Issues & Troubleshooting

HeartCast Won't Start / Returns to Start Screen #heartcastsupport

Most likely cause: HealthKit Workouts permission wasn't granted during setup or after an update.
Fix: Settings → Health → Apps → HeartCast → Enable Workouts toggle.

See HealthKit Permissions for detailed instructions.

Heart Rate Shows Zero or Won't Update

  1. Check that HeartCast version matches on Watch and iPhone (see Version Sync)
  2. Force restart HeartCast on Watch (see instructions)
  3. Verify Health permissions are enabled

Bluetooth Connection Issues

  • Keep HeartCast open and visible on iPhone during initial connection
  • Don't pair HeartCast in iPhone Bluetooth settings. Instead, connect to HeartCast through your equipment's heart rate settings
  • Try connecting HeartCast before other Bluetooth devices (speakers, headphones)

Watch Shows "Ensure your Watch is nearby and press Start"

This appears when:

  • The Watch app isn't running HeartCast
  • Watch is out of Bluetooth range
  • Watch and iPhone aren't syncing properly

Fix: Open HeartCast on your Watch and press Start. If it persists, try force restarting HeartCast on the Watch.

Version Sync Issues #heartcastsupport

After iOS or watchOS updates, sometimes the HeartCast iPhone and Watch apps get out of sync. HeartCast should alert you with a warning.

Check Your Versions

Triple-tap the HeartCast logo on both your iPhone and Watch. The version number will briefly appear.

Both should show the same version (e.g., "3.2.1").

Force Update the Watch App

If versions don't match:

  1. Open the Watch App on your iPhone
  2. Scroll down to find HeartCast
  3. If an update is available, install it
  4. Alternatively Reinstall HeartCast:
    1. Toggle off "Show App on Apple Watch". This will remove the old HeartCast App from your Watch.
    2. Toggle on "Show App on Apple Watch". This will install the newest HeartCast version.
    3. Here's an instructional video on our Instagram

Restarting HeartCast on Apple Watch

Standard Restart

  1. Open HeartCast on your Watch
  2. Double-press the Digital Crown to show recent apps
  3. Swipe left on HeartCast to reveal the red X
  4. Tap the X to close HeartCast
  5. Reopen HeartCast from your app list

Force Quit (when standard restart doesn't work)

  1. Open HeartCast on your Watch so it's visible
  2. Press and hold the side button until the power-off screen appears
  3. Release the side button (do NOT press shutdown)
  4. Press and hold the Digital Crown until HeartCast closes
  5. Reopen HeartCast

Apple Watch-Only Mode (Not Supported) #heartcastsupport

Q: Can I use HeartCast with just my Apple Watch to connect to my bike computer?

Unfortunately, no. Apple does not permit apps on Apple Watch to broadcast Bluetooth signals to external fitness equipment. The iPhone is required as a "Bluetooth bridge" between your Watch and your fitness equipment.

How it works:

  • Watch → (internal connection) → iPhone → (Bluetooth) → Fitness Equipment

You must have your iPhone present during workouts to broadcast your heart rate.

Same-Device Limitation #heartcastsupport

Q: Can HeartCast connect to apps running on the same iPhone?

No. HeartCast broadcasts your heart rate out over Bluetooth to external devices. It cannot connect to apps running on the same iPhone.

Workaround: Use an iPad for the fitness app.

  • Example: HeartCast on iPhone broadcasting to Zwift/TrainerRoad on iPad

Apple Workouts & Health

HeartCast creates a workout session to monitor your heart rate. This is a technical requirement from Apple, HeartCast cannot read heart rate data without an active workout.

Activity Rings

Your workout will contribute to closing your Apple Watch Activity rings, regardless of whether you save the workout data.

No Duplicate Data

Apple Health automatically normalizes data from multiple sources (Watch, iPhone, apps). You won't see duplicate steps or calories from using HeartCast alongside Peloton or other apps.

Workout Exclusivity

Only one workout can run at a time. Starting a workout in another app (Apple Workout, Peloton app, etc.) will stop the HeartCast workout and disconnect from your equipment.

Workout Saving Preferences #heartcastsupport

HeartCast lets you control whether workout data is saved to Apple Health.

Settings → Workout Save Preference:

  • Always Save: Workouts are automatically saved
  • Never Save: Workouts are discarded (activity rings still update)
  • Ask Me: Prompts you after each workout

Note: Even with "Never Save," your Activity rings will still be updated based on activity (Since HeartCast Inception). However, the workout will not be saved.

Heart Rate Zones

HeartCast uses the Karvonen method (Heart Rate Reserve formula) to calculate zones. This considers your Resting Heart Rate for more accurate zone calculations.

Why HeartCast and Peloton Show Different Zones

HeartCast sends only your BPM to Peloton. Each platform calculates zones independently:

  • Peloton uses a simpler max-heart-rate formula
  • HeartCast uses Heart Rate Reserve (includes resting heart rate)

Match Peloton's Zones

To match Peloton's zone calculations, set your Resting Heart Rate to either 0 or 50% of your usual RHR in HeartCast User Preferences.

Settings & Permissions Reference

HeartCast requires these permissions to function:

iPhone Settings

  • Settings → Privacy & Security → Health → HeartCast (iOS 17+)
    or Settings → Health → Apps → HeartCast (iOS 16 and earlier)
    • Enable: Heart Rate, Workouts, Active Energy
  • Settings → HeartCast → Bluetooth: Must be enabled

Apple Watch Settings

  • Settings → Health → Apps → HeartCast: Enable all data types
  • Settings → General → Background App Refresh → HeartCast: Enable

AirPods Pro 3 Heart Rate

AirPods Pro 3 can measure your heart rate during workouts. When you use HeartCast or other workout apps, AirPods Pro 3 measure your heart rate continuously during the session.

How It Works with Apple Watch

If you're wearing both an Apple Watch and AirPods Pro 3 during your workout, they work together to provide multiple streams of heart rate data for better coverage. The highest-confidence source at any moment is automatically used to provide heart rate data to HeartCast.

This means you get the best of both sensors, no configuration needed.

Troubleshooting

If you don't see your heart rate updating:

  • Check your AirPods settings in the Settings app
  • Ensure your AirPods Pro 3 fit properly in your ears
  • Verify HeartCast has the required HealthKit permissions

For more details, see Apple's guide: Track heart rate during workouts with AirPods Pro 3

Contact Support

HeartCast is developed by a solo developer. Response times vary, but I read every message.
Please do email us with bug reports and/or feature requests.

Email: contact@heartcast.app

Social Media:

FAQ last updated: December 2025

Popular tags

apple watch heart rate monitor apple heart heart rate
Download on the App Store