So, I've been using Apple's Health app, and I think it's wonderful.

My Apple Watch frequent enters my heart rate and steps-taken into the database, and I can manually enter other common things like my blood pressure and weight. Cool.

However, I don't see fields for everything that I may want to track.

For example, there aren't any fields to keep track of so-called 'healthy' fats, like DHAs / Omega-3 fatty acids.

I know that there are 3rd party apps that keep track of this sort of thing. But they seem to store that data in their own internal databases. I haven't found an app that can write data to the Health database. That is, unless the field already exists.

So, that has led me to wonder: Is Apple the sole provider/decider of the fields that can be used in their Health app?

Or, is it possible for 3rd party apps (or just a regular user like me) to create new fields that will work in the Health app?

1 Answer 1


Neither you nor third-party developers can add fields to Health.

Working with the HealthKit Framework

The HealthKit framework is designed to share data between apps in a meaningful way. The framework constrains the types of data and units to a predefined list, ensuring that all apps understand what the data means and how it can be used. Developers cannot create custom data types or units. Instead, HealthKit provides a wide variety of data types and units.

HealthKit | Apple Developer Documentation

  • Your excerpt is interesting, but I don't understand how it supports your claim that custom fields cannot be added. Your posted excerpt refers to "types" (such as integer or float) and "units" (such as Celsius or milligrams). It doesn't say anything about why a third party cannot create a custom field. Will you please clarify? ("Field" not be the proper term here since it looks like HealthKit is programmed with OOP, but hopefully you know what I mean.)
    – EJ Mak
    May 23, 2017 at 19:05
  • 1
    @EJMak type is never a good word to see in a definition as it is not well defined:) In this case read the document in "Properties of Objects and Samples" you will find more exact defintions. Types are predefined and they are a name for what is beiung sampled/
    – mmmmmm
    May 23, 2017 at 19:26
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    @EJMak A ‘data type’ in Health is a type of data stored, i.e. a row in the Health app, not what you'd call a type in programming. ‘Developers cannot create custom data types or units’ therefore you cannot create these.
    – grg
    May 23, 2017 at 23:43

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