Check your HR settings in the Mi Fit app.
When the Mi Band is in “Sleep Assistant” HR mode in Mi Fit, it doesn’t feed the HR data to Mi Band Tools / Sleep as Android. When it is in regular HR tracking mode (24-hour), it works.
Due to an issue in our Tasker integration, we had to disable it by default in one of the releases in mid-2017. Please go to Settings – Service – Taker and re-enable it there. Sorry for the trouble.
This is a bug in S Health that the S Health team promised to be fixed way back in S Health v4.6, but didn’t.
We got the following guide on how to resolve this S Health issue from the Samsung S Health team:
In order to resolve this issue, user can try either one of following:
1) Clear S Health data from Android Settings > Applications > S Health > Clear data.
2) Change the locale of the phone and wait 1 day.
For a list of currently supported devices, go here. There is also a list of devices that we cannot possibly integrate.
If you’d like us to integrate another device, please add it as a suggestion to our Uservoice. Also please check whether the device has an API so we can integrate it.