Too Long; Didn't Read
This blog post gives insight on how Swift can be used to fetch and preprocess HealthKit data and how to use CreateML to create a simple classifier that uses that data. As a bonus, very little knowledge of Machine Learning is required for following the implementations and I will give some insights on how to interpret the results. The blog post is designed to guide you through the whole process, though some basic knowledge of Swift coding is useful if you wish to understand everything that is going on.