EDIT: You do have to consent to give Zwiftpower the right to display that information. If you haven’t already, feel free to follow the steps on their website after logging in so you can agree to their terms and conditions.
If you’ve already gone through that process, the check box for sharing your heart rate information might not have been selected. You can select that by going to your “Settings” tab then click on the check box under the “Registration and Privacy Settings” section.
Have you opted in to share your information with Zwiftpower? You can do that here: https://my.zwift.com/profile/connections
Also, check the official Zwiftpower website FAQto see what information from your ride they record and display. This may clear up why that information may not have been available. :)
We’re here if you have any additional questions!