Hi my Apple Watch heart rate “ chart unavailable “ what should I do ?

Hello chhinh,

Thanks for taking the time to post your question to Apple Support Communities. We understand that you're experiencing some issues with your Heart Rate chart.

First, we'd recommend confirming that Power Saving Mode isn't enabled on your Apple Watch as this would turn off the heart rate sensor to conserve power. Use the Workout app on your Apple Watch

Clean the sensor on the back of your Apple Watch and ensure there's no damage present. How to clean your Apple Watch

For the best results, you'll also want to confirm that your watch is the correct fit: Wearing your Apple Watch

After completing these steps, if you're still experiencing issues with your Apple Watch reading your hear rate, contact Apple Support here: Get Support

Regards.