We reported on this in May, and now Garmin has just put up a corresponding support page online stating that it will support data transfer to Google Health Connect in the near future. The support page lists which data is transferred, which includes a variety of activity and wellness data.
However, Garmin states from the outset that data transfer is only one way, meaning that data is sent from Garmin Connect to Google Health; Google Health cannot access data from Garmin Connect. This could certainly be a limitation in certain circumstances: If a different wearable is used in everyday life than for sports, for example, Garmin Connect will not have a complete picture of the user's overall physical activity, which may influence suggestions from Garmin Connect in regard to optimization of training and well-being.
As previously stated, a variety of activity and wellness related data can be transferred from Garmin Connect to Google Health, as well as a small tidbits of user-specific data. For example, body fat content and weight - which can be recorded using a corresponding scale - can be transferred, as can step count, sleep data and calories burned. Heart rate data from activities can also be transferred, as well as the number of swimming strokes and data on cycling speed and cadence.