Hi
The Health app on iPhone combines data from Apple Watch, iPhone and any other sources for which sharing permission has been granted, along with any data that you may enter manually.
With the Activity app set up and other relevant options enabled, Apple Watch can contribute data including, for example:
- Walking + Running Distance.
- Active Energy.
- Steps.
- Resting Energy.
- Workouts.
- Stand Hours.
- Exercise Minutes.
- Heart Rate (from the watch's built-in heart rate sensor).
- Mindfulness Minutes (from the Breathe app ).
Other data may also be contributed by Apple Watch, depending on how it is used (for example, swimming distance with Apple Watch Series 2).
iPhone can also contribute data including:
- Walking + Running Distance.
- Flights Climbed (stairs).
- Body measurements (when entered on the iPhone).
When it receives data of the same type from different sources for the same time period, the Health app adjusts the information it reports to avoid any double-counting.
A wide range of third-party apps and accessories can also be used to share information to the Health app.
More information:
http://www.apple.com/ios/health/
Use the Health app on your iPhone or iPod touch - Apple Support
Manage Health data from multiple sources on your iPhone, iPod touch, or Apple Watch - Apple Support
