The Google Health Data API is designed to enable developers to do two things:
Read a user's Google Health profile or query for medical records that match particular criteria and then use the results to provide personalized functionality based on the data.
Add new medical records to a user's profile by including CCR data when sending a notice to a user's profile. Note: The CCR data is stored as an XML blob within the <atom> entry. The library does not provide direct accessors to the object model but it does have helpers for extracting specific fields.
There are three main feeds, each of which requires authentication. Unlike other Google Data APIs, each Google Health feed has a limited set of HTTP operations you can perform on it, depending on which authentication method you are using (ClientLogin or AuthSub/OAuth). For a list of permitted operations, see http://code.google.com/apis/health/reference.html#Authentication.
Profile Feed use the profile feed to query a user's health profile for specific information.
Register Feed use the register feed to reconcile new CCR data into a profile.
Profile List Feed the profile list feed should be used to determine which of the user's Health profiles to interact with. This feed is only available when using ClientLogin.
See http://code.google.com/apis/health for more information about the Google Health API.