PHP SDK

There really is no SDK to access the Health data as such.

There is a "Confidential"  specification ( Health_REST_API_Specification_2.9.6_Worldwide.pdf)  which contains much of the material required to access the health API and which is provided to "approved developers" once you have completed Garmin's approval process 

Thanks for the reply. I saw that document and am wondering what's the best way to implement it in PHP. If you've done it before, could you please share some code? Thank you.

Yes, but only with a great deal of invaluable assistance from the Health team, I have implemented an app in PHP. 

In which area do you require assistance? Please outline your app and current stage of development of the Health API. 

I will need access to all APIs available

Really? Is this a genuine app?

Yes, it is genuine, why are you asking?

Due diligence.

The Health API is a RESTful API that returns activity summaries and daily summaries as JSON. There is no SDK for working with the Health API, since implementing a RESTful client is dependent on the tech-stack you are working with. With the Health API, there is an option to get the original FIT file for activities. But first you need to implement a RESTful client to retrieve the files and only then you can use the FIT SDK to decode the files.

You can apply for access to the Health API at the link below, and the the Health API team will work with you to decide if your project is right for the Health API and how best to use it.
developer.garmin.com/.../

Once you have access to the Health API, there is a private support forum available in the developer portal where you can ask questions specific to the Health API.

I’ll be able to assist once you have access to the Health API and have a specific question. It is not appropriate for me to dump a bunch of code as I will first have to redact confidential sections.