Running guides
How to record heart rate while running: Apple Watch or Bluetooth monitors
An iPhone can use Apple Watch or connect directly to a compatible BLE heart rate strap or armband. Learn how to connect a device, check permissions and troubleshoot missing readings in AimiRun.
If the average heart rate is missing from a saved run, first check whether a heart rate source was connected during that run. AimiRun can receive readings from Apple Watch or a compatible Bluetooth device, but it does not calculate heart rate from pace or cadence.
You do not need an Apple Watch to record heart rate with an iPhone. You can connect a compatible BLE heart rate strap or armband directly to your iPhone and let AimiRun receive its readings.
On iPhone, choose Apple Watch or a compatible BLE device connected directly to the phone. Android and Harmony phones can use BLE devices supported by the current app version. After connecting, make sure the readings update. Connecting after a run cannot recreate data that was never recorded.
Choose a connection method
| Device you have | Phone | Where to set it up | Check before running |
|---|---|---|---|
| Apple Watch | iPhone paired with the watch | Me → Apple Watch | AimiRun is installed, Watch use during runs is enabled, and requested permissions are granted |
| Compatible Bluetooth heart rate strap or armband | iPhone, Android or Harmony, where supported by the current version | Me → Bluetooth heart rate | The device is awake and connected, and the page receives readings |
| A device that only shows heart rate in its maker's app | Check compatibility first | Check whether it can broadcast heart rate to other apps | Measuring heart rate does not necessarily mean it can send readings to AimiRun |
You only need one working source. Set it up before your run and confirm that it provides readings.
Record heart rate with Apple Watch
This option uses an Apple Watch paired with an iPhone. These steps describe starting a run in AimiRun on the phone.
- Install AimiRun on the watch. If it is not installed, look for it in the Watch app on your iPhone or in the App Store on the watch.
- Open “Me → Apple Watch” in AimiRun on your phone. Check the watch status and enable “Use Apple Watch During Runs”. Pairing the watch in iOS alone does not enable AimiRun’s watch feature.
- Grant the requested permissions. On first use, allow the workout and heart rate access requested by the watch app. If you previously denied access, check the system settings.
- Wear the watch and start the run from your phone. Make sure the watch enters AimiRun's running screen, then check whether heart rate appears. It may take a little time for the first reading.
If no reading appears, check that the watch fits snugly against your skin and that heart rate is enabled in the Watch app's privacy settings. See Apple's guidance on wearing Apple Watch and getting accurate measurements.
“Save Runs to Apple Health” and “Use Apple Watch During Runs” are separate settings. The first saves workout records. To receive heart rate during a run, enable watch use, grant access and have the watch participate in the recording.
Connect a Bluetooth heart rate strap or armband
This option works on iPhone and on Android and Harmony phones supported by the current app version. The heart rate device connects directly to the phone; it does not need to connect through Apple Watch.
In AimiRun, open Me → Bluetooth heart rate to add and manage devices.
- Wear and wake the device. If it has a heart rate broadcast setting, enable it as described by the manufacturer. Check its battery. If another app is occupying the connection, disconnect it there and try again.
- Turn on Bluetooth and grant the requested phone permissions. Complete this before running so you are not setting up access mid-workout.
- Tap Add device and choose the device. If it is not found, wake it and scan again. Seeing its name only confirms discovery, not that heart rate is available.
- Wait for the connection and check for readings. If the page still says it is waiting for heart rate data, check fit, broadcast settings and compatibility.
- Make sure “Connect automatically on the next run” is enabled. If you have several devices, use “Set as preferred” for the one to try first. Make sure the device is awake before starting, then check that heart rate keeps updating once the run has started.
Does Bluetooth guarantee compatibility?
No. AimiRun supports standard BLE heart rate devices and some adapted wearables, but devices differ in how they share data. The Bluetooth SIG Heart Rate Service provides heart rate data to fitness apps. A device that measures heart rate in its own app does not necessarily expose that service to AimiRun.
Check the measurement mode shown after adding a device. Continuous, intermittent and single readings provide different experiences. To review changes during a run, the device needs to keep sending readings; a single measurement cannot fill in a whole workout.
Will AimiRun switch between saved devices?
Only one Bluetooth heart rate device is used at a time. You can save several devices, choose a preferred one and allow other saved devices to be tried before the first connection. After a Bluetooth device connects, AimiRun will not switch to another Bluetooth device during that run.
If both Apple Watch and a Bluetooth device are in use, valid readings from the Bluetooth device take priority. AimiRun does not add or average readings from the two devices.
Why is heart rate missing from the running screen?
Check two things: whether readings are arriving and whether heart rate is selected for display. First confirm the connection and permissions on the device page. Then open AimiRun's running-screen metrics and make sure heart rate is included in the layout for this run type. Enabling a device does not automatically add the metric to every layout.
If readings stop updating, check the fit, battery, Bluetooth and connection when it is safe to stop. A “connected” status alone does not prove that new readings are arriving. Cadence has a separate data source, so seeing cadence does not mean heart rate is available. For cadence setup, see the smart cadence guide.
Where can I see heart rate after a run?
Open the saved run to see average and maximum heart rate. If the details show only some metrics, choose “Show all metrics”. You can also review the route and recording in track replay.
If average heart rate is unavailable, the detail shows “Record heart rate →”, which opens this guide. Maximum heart rate appears only when valid data is available. Apple Watch may finish syncing data it already collected after a run; if no usable heart rate was recorded, syncing or connecting later cannot restore it.
Frequently asked questions
Can the phone measure my heart rate by itself?
For heart rate, AimiRun uses Apple Watch or a compatible Bluetooth device. The phone can still record a run without either source, but the app will not estimate heart rate from pace, cadence or calories.
Why can I find a device but still get no readings?
It may not be broadcasting heart rate, may not be worn correctly, or may use a data method that the current app version does not support. Check the device status and actual readings; its name appearing in a scan is not proof of compatibility.
Do I have to pair the device in the phone's Bluetooth settings first?
Follow the device's instructions and add it from AimiRun's Bluetooth heart rate page. A device listed in system Bluetooth settings is not necessarily connected to AimiRun, and does not prove the app is receiving readings.
Can I record a run without heart rate?
Yes. You can continue recording and prepare a device before your next run. Check that the device page receives readings before starting; there is no need to restart a run just to fill in a missing heart rate.
