For the most seamless and accurate treadmill experience, we recommend recording your workout using the Runna app on your phone. Some watches offer a treadmill mode, but this typically relies on accelerometer data and can be less reliable for pace and distance - making indoor recording a bit fiddly.
You can still track health metrics by recording your treadmill workout on both your phone and a compatible smartwatch (Garmin, COROS, Suunto, Amazfit, or Apple Fitness) at the same time. Once both activities are saved, Runna automatically merges data from each device to create the most accurate workout summary:
Runna phone app for more accurate treadmill pace and distance
Your smartwatch for health metrics like heart rate, cadence, and calories
This article covers third-party wearables only. Check out this article to learn how to record your treadmill workout with your Runna Apple Watch App.
Using Your Compatible Watch with a Smart Treadmill
Follow these steps to use your FTMS-compatible Smart treadmill with Runna:
Get set up
Connect your earphones to your phone (optional)
Turn off Auto Lap on your watch
Start the workout in the Runna app
Open the Runna app on your phone
Go to Today → Workout → Start Workout
Select Treadmill Run
Connect to your treadmill
Tap Connect Treadmill
Select your treadmill from the list of available devices
Wait for the connection to confirm
Start your run:
Press Start in the Runna app to begin the workout
On your compatible smartwatch, start a regular Treadmill Run within 60 seconds of starting the workout in the Runna app. During the workout, don’t interact with your watch - let it run freely in the background (including during rest periods).
Finish and save your workout on both your phone and watch as normal
Once your watch syncs to your phone, the phone and watch activities will merge automatically in the Runna app.
Using Your Compatible Watch with a Manual Treadmill
Follow these steps to ensure your workout and health metrics merge correctly:
Connect your earphones to your phone (optional) and turn off Auto Lap on your watch
Start the workout in the Runna app:
Open the Runna app on your phone
Go to Today → Workout → Start Workout
Select Treadmill Run
On your compatible smartwatch, start a regular Treadmill Run within 60 seconds of starting the workout in the Runna app.
Don’t interact with your watch during the workout - let it run freely in the background (including during rest periods)
Once finished, press and hold to end the workout on your phone, and save your watch recording as normal.
Before saving your workout in the Runna app, adjust the lap distance/speed/time of your workout to reflect what you actually completed
Tap Save
Once your watch has synced to your phone, the phone and watch activities will merge automatically in the Runna app.
Can I combine an outdoor warm-up / cool-down with an indoor treadmill workout?
This is a tricky scenario as Runna doesn't currently support splitting a single workout between outdoor and treadmill recording modes. Here are your best options:
Option 1: Record as three separate activities
Outdoor warm-up
Start your planned workout on your watch as you normally would for an outdoor run
Complete your warm-up run to the gym
End and save the activity when you arrive
Treadmill intervals
Open the Runna app on your phone
Go to Today → Workout → Start Workout → Treadmill Run
If you want heart rate data, start a free treadmill run on your watch within 30 seconds of starting the phone recording
The phone and watch activities will merge, giving you accurate distance plus health metrics
Outdoor cool-down
Start the planned workout on your watch again (or a free outdoor run)
Complete your cool-down run as normal
End and save the activity
This will record your session as three separate activities, but it’s the most accurate option. You can manually link all three parts to your planned workout afterwards by opening the planned workout and tapping Link activity multiple times.
Please note that these activities will not merge together - they will remain as three separate recordings.
Option 2: Record the entire session as one outdoor activity
If you’d prefer everything to stay as one workout, you can record the whole thing (warm-up + treadmill intervals + cool-down) as a single outdoor run on your watch.
Keep in mind that the treadmill portion will be less accurate because GPS won’t work properly indoors and your watch will estimate pace and distance. For best accuracy during the treadmill section, start the workout in the Runna app on your phone and skip to the interval section. You can delete the duplicate phone recording afterwards if needed.
FAQs
What wearable devices are supported for merging workout data?
This merging functionality currently supports:
Garmin
COROS
Suunto
Amazfit
Apple Fitness
Why aren’t my activities merging?
To merge correctly, make sure you start your watch treadmill run within 60 seconds of starting the Runna workout on your phone. If the watch recording starts too late, the activities may not merge as expected.
Why isn't my data merging from Apple Fitness?
Please check that your:
iPhone is running iOS 18.3 or later
Apple Watch is running watchOS 10.0 or later
Then check your permissions:
In the Runna app:
Go to Profile (top left) → Connected Apps & Devices → Apple Health
Ensure Sync Completed Workouts is toggled ON
Then go to: Connected Apps & Devices → Apple Watch
Ensure Sync Completed Workouts is toggled ON
In the Apple Health app:
Go to Profile picture → Privacy → Apps → Runna → Allow Runna to Read
Ensure Workout Routes and Workouts are toggled ON
If permissions look correct, try the following:
Check you finished and saved your workout on your watch within 60 seconds of your phone recording.
Try manually importing your workout to Runna:
Go to Connected Apps & Devices → Apple Health and look for activities with an Import button
Restart both your iPhone and Apple Watch
Make sure Auto Lap is turned off on your Apple Watch, as this can cause mismatches between recordings
If you're still having trouble after trying these steps, please let us know via the in-app support tab and we’ll do our best to help.
Why isn't my data merging from my third-party watch (COROS, Garmin, Suunto, Amazfit)?
First, make sure you finish and save your workout on your watch within 60 seconds of stopping the recording on your phone. If the activities are saved too far apart, Runna may not be able to merge them.
If that looks good, try the following steps:
Disconnect and reconnect your smartwatch in Runna: Go to Profile → Connected Apps & Devices, disconnect your watch, then reconnect it.
Make sure the Runna app is up to date and running the latest version.
Manually trigger a resync between your smartwatch and its companion app (for example, Garmin Connect).
Turn off Auto Lap on your smartwatch, as this can cause mismatches between recordings and prevent merging.
If you’re still having trouble after trying these steps, check out our Garmin Troubleshooting article or contact us via the in-app support tab and we’ll do our best to help!
Why isn't my data merging from Amazfit?
If the steps above don’t resolve the issue, it’s important to note that Runna workout syncing is currently only supported on the following Amazfit models:
Amazfit T-Rex 3 Pro
Amazfit Balance 2
We’re actively working with Amazfit to expand support to additional devices. For now, only these two models can receive and sync Runna workouts on the watch.
Need more support?
If you have any further questions or run into issues recording your treadmill workouts, please reach out via the in-app support tab and we’ll do our best to help!