Can not measure heart rate on my Apple watch

Thanks for asking about the new ECG feature.

Check here for availability in your region: ECG

ECG requires the current non-beta version of iOS and watchOS. For additional help with the ECG feature on your Apple Watch, take a look at these articles.

Heart rate notifications on your Apple Watch - Apple Support

Taking an ECG with the ECG app on Apple Watch Series 4 or later - Apple Support

If you have any other questions please reach out to our team here: https://apple.co/HeartFeatures. If you believe that you are experiencing a medical emergency, please dial your local emergency services.

Take care 

Perhaps this article will help:

Your heart rate. What it means, and where on Apple Watch you’ll find it. - Apple Support

Get the most accurate measurements using your Apple Watch - Apple Support

Does your watch have the ECG app?

Is your watch in power reserve mode?

Do you have compatible software on phone and watch?

Has the ECG app been approved in your country?.

For the ECG app to work on your watch the ECG app has to be approved by;

1. the government of the country in which the watch was bought and

2.the government of the country in which you reside.