Hi
Heart rate
Apple advises that, even under ideal conditions, Apple Watch may not be able to record a reliable heart rate reading every time for everybody.
For the best performance from the heart rate sensor during workouts, ensure that you wear your watch snugly (but not too tightly) on the top of your wrist, as you have indicated that you are already doing. Apple suggests that you consider tightening the band before starting a workout and loosening it again afterwards:
Wearing your Apple Watch - Apple Support
The sensor is likely to give better results for workouts that involve rhythmic (eg running) rather than irregular (eg boxing) movements. Other issues that can impact sensor performance include skin perfusion and wrist tattoos:
For any workouts that involve flexing your wrists - such as when lifting weights - it may help to move your watch a little higher up your arm, away from the flexing joint.
It may also help to check that the back of your Apple Watch is clean (along with your wrist, which I'm sure is the case):
Cleaning your Apple Watch - Apple Support
If you continue to experience issues with recording your heart rate during workouts, then, for more consistent readings, you may wish to consider pairing an external heart rate monitor / Bluetooth chest strap to your Apple Watch:
Use Bluetooth accessories with your Apple Watch - Apple Support
If you are concerned about a possible hardware defect with your Apple Watch, 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:
Distance
The following steps may help:
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.
Reset your existing calibration data and recalibrate your Apple Watch:
- Calibration can improve the accuracy of estimations made by Activity app and Workout app, including when GPS reception is not available.
- More information and instructions are available via the link below:
- Resetting your calibration data and following detailed instructions for calibrating your Apple Watch can be equally as helpful for Series 3 models and will not erase your Activity history.
Be sure to allow the arm on which you are wearing your Apple Watch to swing naturally during relevant workouts (and also during calibration).
