Hi
If your exercise levels are broadly unchanged, but your Activity app estimations have changed significantly, then the following steps may help to prevent the issue from happening again:
If you have not yet done so, update your iPhone and Apple Watch to the latest compatible software versions, starting with your iPhone:
Check your personal information:
- Actiivity-related estimations depend, in part, on your personal information. To check that this is accurate:
- On your iPhone, in the Watch app, go to: My Watch (tab) > Health > Edit - tap and adjust items, then tap on Done.
- If the setting for Wheelchair currently states "Not Set", then change it to "Yes" or "No" as appropriate.
Check that Wrist Detection is turned on and that, if passcode is enabled, you are unlocking your Apple Watch after placing it on your wrist:
- On your iPhone, in the Watch app, go to: My Watch (tab) > Passcode > turn Wrist Detection on.
Record any specific fitness activities using the Workout app (or a third-party app that shares data to Health), choosing the activity type that most closely matches your workout, including choosing Other for workouts that are neither included within nor sufficiently similar to those in the main list.
Check the Workout app - and, if you have ever previously (not necessarily recently) used any third-party fitness or sleep tracking apps to record workouts on your watch, also check them on your Apple Watch - to see whether there is an active or paused session within any of them.
- If there is, then end that session from within that app on your Apple Watch (not your iPhone).
- If in doubt, remove any such third-party apps from your Apple Watch.
Check that you are wearing your Apple Watch sufficiently snugly on the top of your wrist:
- If your Apple Watch is worn too loosely, it can believe that it has been removed, causing activity to not be tracked.
- For the best performance from your Apple Watch - including the most accurate readings from the heart rate sensor, which is used continually during workouts - be sure to wear your Apple Watch snugly (but not too tightly) during your workouts.
- Apple suggests tightening your Apple Watch band before workouts and loosening it again afterwards:
Close certain apps and restart both your iPhone and your Apple Watch:
- Close the Watch app, Activity app and Health app (if open) on your iPhone:
- Double-click the Home button, then swipe up on each app preview to close the apps.
- Turn both devices off together, then restart your iPhone first:
Check your Location Services settings:
- On your iPhone, go to: Settings > Privacy > Location Services:
- Check that Location Services (the main setting at the top) is turned on.
- In the list of apps beneath, check that Apple Watch Workout is set to While Using.
- Also enable options under System Services including Motion Calibration & Distance, Wi-Fi Networking and Mobile Network Search.
- If the settings are already enabled, try briefly turning them off and then back again.
Reset your existing calibration data and recalibrate your Apple Watch:
- Calibration can improve the accuracy of estimations made by Activity app and Workout app.
- More information and instructions are available via the link below:
- Resetting your calibration data can be equally as helpful for Series 2 & 3 models and will not erase your Activity history.
If the issue persists, then it may help to unpair and re-pair your Apple Watch:
If the issue still persists, then I suggest that you contact Apple Support (remote diagnostics and/or mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider for assistance:
More information:
Get the most accurate measurements using your Apple Watch - Apple Support
Use the Activity app on your Apple Watch - Apple Support
Work out with your Apple Watch - Apple Support
Your heart rate. What it means, and where on Apple Watch you’ll find it. - Apple Support