As more and more patients use wearable devices and smartphone apps to track their personal health data, how can this information be used in a meaningful way? Fitness technology companies like Fitbit and Apple Health are leveraging insights from over 10 years of activity, exercise, and sleep data to better inform future applications and provide behavior change techniques and insights to their users. Apple recently announced that customers in the USA can enroll in three landmark health studies: the Apple Women’s Health Study, the Apple Heart and Movement Study, and the Apple Hearing Study. Conducted in partnership with leading academic and research institutions like the World Health Organization, these multi-year longitudinal studies are leveraging the ubiquity of Apple products to provide a treasure trove of user data to inform potential medical discoveries that could improve healthcare for all [14].