Getting started with HealthKit

Description: HealthKit helps you build world-class health and fitness apps by centralizing health data from third-party apps, iPhone, Apple Watch, and external health devices. Discover how you can manage authorization and privacy around Health data, read and write data to the shared Health Store, and use HealthKit’s built-in queries to fetch data and calculate statistics for that data.

What's HealtKit?

HealthKit is a framework that creates a central repository of all the user's health data, allowing applications to read data from it and also contribute data to it.

We can interact with health data on multiple devices including our iPhone, Apple Watch, and iCloud.

How to build a HealthKit app

Three steps:

  1. Setup HealthKit
  2. Save data to HealthKit
  3. Read and display HealthKit data

Setup HealthKit

Save data to HealthKit

All different types of health data are stored as Health Samples (HKSample).

Health Samples are all structured in a very similar pattern:

  • they have an associated type of data that they represent
  • the value of that type of data
  • the time these health events occurred
  • meta-data representing any additional information about these samples

To save data to HealthKit:

  • Request write access to HealthKit
  • Create Health samples
  • Save the samples via the HealthStore

Read data from HealthKit

HealthKit offers queries to read HealthKit data

To read data from HealthKit:

  • Create a query object, for each object you'll need to define:
    • the type of data that you want to read
    • a filter (predicate) that will restrict the results returned from your query
  • Execute the query via the HealthStore

Missing anything? Corrections? Contributions are welcome 😃


Written by

Federico Zanetello

Federico Zanetello

iOS Engineer with strong passion for Swift, minimalism, and design. When he’s not busy automating things, he can be found writing at FIVE STARS and/or playing with the latest shiny toys.