The Fitbit Charge 6 packs a lot of sensors into that slim bracelet, but none of them matter if the watch can't tell what you're doing. Activity tracking dropping out mid-run, steps not counting, or your heart rate staying flat during a workout often comes down to the fit or a permission that got reset.
The fastest thing to check is how the Charge 6 sits on your wrist. The optical heart rate sensor needs consistent skin contact, and if the band is too loose it can lose tracking.
Start with the fit on your wrist
Slide the Charge 6 up your forearm so it sits about a finger-width above your wrist bone. The band should be snug enough that the watch doesn't slide around when you move your arm, but not so tight that it leaves deep imprints.
During workouts, a loose band can cause gaps in heart rate tracking. Adjust the band for a snug, comfortable fit before you start any tracked activity.
Clean the sensor array on the back
The Charge 6 uses green and infrared LEDs to measure heart rate, and any film on the back lens scatters that light. Sweat, sunscreen, and dried skin oil are the usual culprits, and they build up fast if you wear the watch all day.
Wipe the back of the Charge 6 with a damp microfiber cloth before a workout. Avoid alcohol or harsh cleaners, plain water is all you need. Dry it with a soft towel and pop it back on.
Check Google Health app permissions on your phone
If workouts aren't syncing, the Google Health app may be missing permissions it needs. On Android, open Settings > Apps > Health > Permissions and check Location and Nearby devices. Physical activity lets your phone track health and fitness. For iPhone syncing, go to Settings > Privacy & Security > Bluetooth and allow Google Health. Motion & Fitness, when needed for phone-based tracking, is under Settings > Privacy & Security > Motion & Fitness.
Missing permissions can interfere with syncing and connected GPS. If a message appears at the top of the Google Health app, tap it to fix missing permissions or connection requests.
The side button is haptic, not mechanical
The Charge 6 has a haptic side button. For best results, place your thumb and index finger on opposite sides of the tracker and squeeze to press it.
Squeeze the tracker between your thumb and index finger to press the button.
Turn off battery optimization for the Google Health app
Android battery settings can restrict the Google Health app in the background. When the app can't run in the background, automatic syncing can stop, connected GPS can lose its connection, and firmware updates may not finish.
On Android, open Settings > Apps > Health > App battery usage. Turn on Allow background usage, tap it, and choose Unrestricted. Exact steps vary by phone. On iPhone, make sure Background App Refresh is on for the Google Health app under Settings > General > Background App Refresh.
Force restart the Charge 6
If activity tracking was working yesterday and stopped today, try restarting the Charge 6. A restart turns it off and on without losing activity data and can help when it isn't registering steps or other data.
Swipe down from the clock screen and open Settings > Restart Device > Restart. If the Charge 6 is unresponsive, connect it to its charging cable. Press the button on the flat end of the charger three times, with a one-second pause between presses, then wait 10 seconds or until the Fitbit logo appears.
Update the firmware and the Google Health app
Check whether a firmware update is available for your Charge 6. Keeping the firmware up to date can help with troubleshooting activity tracking problems.
Open Google Health with your Charge 6 nearby. At the top left, tap Connections > Charge 6 > Update, when available. Follow the prompts and keep the app running and tracker nearby; connecting the charger is recommended.
While you're at it, check that the Google Health app itself is up to date from your phone's app store.
Make sure your Google Account is connected
If you're having trouble accessing your activity data, check that you're signed in to the Google Health app with the same account you used to set up your Charge 6. This is especially useful to check after switching phones.
If you can't sign in on Android, check your phone's time settings. Open Settings > System > Date & time and turn on Automatic date and time. A manually set time can interfere with signing in to the Google Health app.
Take a GPS run to update stride length
Stride length affects the distance calculated from your steps, rather than the number of steps counted. If your distance seems high or low, updating your stride length may help. A GPS run can automatically update it.
Open the Exercise app on the Charge 6, choose Run, and record a GPS run lasting at least 10 minutes to update stride length automatically. The Charge 6 has built-in GPS + GLONASS, so it can track your route and pace on its own even without your phone.
Disable auto-track if workouts start late
The Charge 6 automatically detects walks, runs, and outdoor cycling. But automatic workout detection may start later than you want. If you're regularly losing the start of your workouts, switch to manual tracking so you can choose when the recording begins.
On Charge 6, swipe left or right to open Exercise, swipe up to find your activity, and tap it. Tap the play icon when you're ready to start.
Go ahead and turn off auto-detection if you always start workouts manually. In Google Health, tap your profile picture > Google Health Settings > Activity. Under Activity settings, select an activity and turn off Detect automatically. For Charge 6 workout-start prompts, adjust Auto-start in the tracker's Exercise app.
Check activity data and restart if needed
Daily activity data can't be deleted, so clearing it isn't a way to recalibrate the Charge 6. Check your activity stats on the tracker and in the Google Health app to see whether the discrepancy appears in both places.
If the tracker isn't registering steps or other data, swipe down from the clock screen and open Settings > Restart Device > Restart. This restarts the Charge 6 without losing activity data. Once it restarts, check your activity stats again.