To connect your Google Fit, tap on the Settings tab (represented by a gear) and check "Connect to Google Fit".
To make the sync more reliable, follow these tips:
- Have both applications open at the same time.
- If you have multiple Google accounts on your phone, please make sure you are viewing the same Google account on Google Fit as what you have selected when connected to Instant Heart Rate with Google Fit.
Please refer to this article to connect to Apple's Health App.