If calories are not being recorded by the Activity app or Workout app, then the following steps may help (check after each):
If you have not yet done so, update your iPhone and Apple Watch to the latest software, starting with your iPhone:
Check that you have set up the Activity app:
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 fitness tracking settings:
- On your iPhone, in the Watch app, go to: My Watch (tab) > Privacy - turn on Heart Rate and Fitness Tracking.
- On your iPhone, go to: Settings > Privacy > Motion & Fitness - check that both Fitness Tracking and Health are enabled.
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.
Check that you are wearing your Apple Watch correctly:
- 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) on the top of your wrist.
- Apple suggests tightening your Apple Watch band before workouts and loosening it again afterwards:
- Sensor performance can be affected by skin changes, such as by some wrist tattoos.
Calibrate your Apple Watch, resetting any existing calibration data and starting afresh. Follow the instructions here (this process can be equally beneficial for Series 3 models):
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:
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