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

• Real-Time Data Sync:  
  

• The Apple Watch integration initiates its first API call when a participant joins the project, retrieving any retrospective data. During the study period, a single API call occurs daily when participants enter the ExpiWell app’s "survey start screen" for the first survey of the day, collecting all available data up to that moment. No further data syncs happen for the remainder of the day, regardless of the number of scheduled surveys.
• On the final day of scheduled surveys, an additional API call is triggered when participants access the last scheduled survey's "survey start screen", capturing data up to that timeslot. This approach allows researchers to monitor participants’ Apple Watch data in real time throughout the study, provided daily surveys are scheduled, even before the study 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

1. On the first day of joining the project in the ExpiWell app, the system retrieves the requested number of days of retrospective data, up to the exact time the participant enters the project (e.g., 10:30 a.m.).

1. On subsequent days, Apple Watch data is collected from the previous API call—either from the prior day or, if there were missed surveys, all missing days are included—until the exact time the participant enters the ExpiWell app’s "survey start screen" for their first survey of the day.
2. On the final day of scheduled surveys, the API is triggered twice:
   
1. When the participant enters the "survey start screen" for their first survey of the day.
2. When they enter the "survey start screen" for their last scheduled survey, capturing data until that timeslot.
   
3. The API is activated specifically at the "survey start screen", as shown below.
   

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.

FAQs

• Yes, as it will be marked as completed.
  

Is it possible to collect Apple Watch data passively without interacting with the ExpiWell mobile app?

• No, passive data collection without app interaction is not feasible because the Apple Watch APIs we use for data collection require app interaction.

What happens if a participant misses a survey? Will Apple Watch data still be collected?

• If a participant misses a survey, Apple Watch data will still be collected for those days. When they complete the next available survey, data from the missed days will be collected along with the current day's data. For example, if a participant misses surveys on Day 2 and Day 3 but completes the survey on Day 4, you'll be able to download Apple Watch data for Days 2, 3, and 4.

What happens if a participant rejoins the project? Will the Apple Watch data be lost?

• No, the previous Apple Watch data will still be saved. Upon rejoining the project, a new Apple Watch data file will be created for that same participant. For example, in the screenshot below, Participant 1 rejoined the project three times and will have four Apple Watch data files, with the latest Apple Watch data file downloadable under Participant 1 (4).