Introduction

The Apple Watch integration enables researchers to seamlessly collect health data from participants while simultaneously gathering self-reported experience sampling data. This integration provides a detailed view of participants' physical activity and health metrics, enhancing research potential in various domains like fitness, sleep, and general well-being.

Key Features

• Health Data Collection: Researchers can collect a range of health metrics from participants’ Apple Watches via the HealthKit app, including but not limited to:
  
  • Step count
  • Heart rate (resting and active)
  • Sleep data
  • Blood oxygen levels
  • Heart rate variability
  • Respiratory rate
    
  • Blood pressure
    
  • Body temperature

Data collection for the various parameters will depend on the available 'Apple Watch' data on the HealthKit app. Data can be collected from all Apple Watch models as long as they are synced with the HealthKit app.

• Real-Time Data Sync:  The Apple Watch integration initiates a single API call daily when participants first open the ExpiWell app. This call collects all available data up to that moment. No additional data syncs occur for the remainder of the day, regardless of the number of scheduled surveys. On the last day of scheduled surveys, an extra API call is made when participants access the last scheduled survey, capturing data up to that survey’s timeslot. This enables researchers to view participants’ Apple Watch data in real-time throughout the study (as long as daily surveys are scheduled), even before it concludes.

• Collecting Retrospective Data: The Apple Watch integration allows researchers to capture past health metrics if the participant wore their Apple Watch before the project began and the data is still available in the HealthKit app. This facilitates the quick collection of baseline data as needed.

How It Works:

1. Web App Setup: 

• Researchers can select up to a maximum of five health data parameters they wish to monitor from the Apple Watch (e.g., heart rate, step count, sleep) through the “Integrations” page.
  

• The setup allows researchers to select how many days of retrospective data they wish to collect before the study begins (e.g., 1 day, 15 days, 30 days). Retrospective data from the HealthKit app will then be collected for the specified number of days from the time the participant joins the project. For example, if 5 days of retrospective data were requested and the participant joins the project on 14th September at 11:15 AM, data from 11:15 AM on 9th September will be collected (as shown in the step count CSV example screenshot). 
  

2. Data Collection Process

On the first day of accessing the project on the ExpiWell app, the requested number of days of retrospective data will be called up to the exact time of the first app opening (e.g., 10:30 a.m.).

For subsequent days, Apple Watch data from the previous API call (either from the previous day or if there were any missed surveys, all the missing days will also be included) until the exact time the participants open the ExpiWell app for the first time each day will be collected.

For the last day, the API will be called twice in that day:

1. When the participant opens the ExpiWell app for the first time in a day
   
2. When the last scheduled survey is accessed for the day (the current day's data is collected until the last scheduled survey timeslot).

3. CSV Download:

• Data from the Apple Watch is stored based on participant actions. For instance, step counts or heart rate data are organized into time periods (with the start and end times specified), and the corresponding number of steps taken, or heart rate measured during that time period (see example CSV screenshots below).
• Separate CSV files for different parameters are available for download.
• Researchers can download all available parameters in bulk. 
  

Step Count CSV sample:

NOTE:  If a participant switches from iOS to an Android device during the study, Apple Watch data will no longer be collected, which may result in incomplete data for the research project.

1. They need to wear their Apple Watch and ensure it is synced with the HealthKit app on their phone.
   
2. Upon starting the project, participants can open the ExpiWell mobile app to complete their first survey of the day, and the app will pull their health data up to that exact time.
   
3. Past data, if available in HealthKit, will also be collected automatically when the project begins, provided it was stored before the start.