Apple’s recent Worldwide Developers Conference (WWDC) keynote was packed with new features for iPhones, Macs and iPads — and like it has done pretty consistently since the debut of its original Health app in 2014, those included updates focused on personal health and wellness. Often, it’s impossible to assess the impact of the work Apple is doing in these areas in the moment, and health-related feature announcements aren’t generally as splashy as user interface overhauls for Apple’s device software, for instance. But viewed as a whole, Apple has built probably the most powerful and accessible suite of personal health tools available to an individual, and it shows no signs of slowing down.

I spoke with Apple Vice President of Technology Kevin Lynch, who actually demonstrated the Apple Watch for the first time on the world stage during Apple’s September 2014 keynote event. Lynch has seen Apple Watch grow considerably during his time at the company, but he’s also been integral to the evolution of its health initiatives. He explained how it became what it is today and provided some hints as to where it might go in the future.

“It’s been amazing how much it’s evolved over time,” Lynch said, referring to the original Health app. “It actually started from Apple Watch, where we were capturing heart rate data for calorimetry activity, and [Activity] ring closure, and we needed a place to put the heart rate data. So we created the Health app as a place to store the data.”

From there, Lynch says Apple realized that once you had this centralized location, they could develop a system that could store other data types, as well, and create an API and architecture that allowed developers to store related data there, as well, in a privacy-respecting way. In the early days, the Health app was still essentially a passive storehouse, providing users one touchpoint for various health-related information, but the company soon began thinking more about what else it could offer, and inspiration came from users.

User-guided evolution

A key turning point for Apple’s approach to health came when the company saw that users were doing more with features available via the Apple Watch than the company ever intended, Lynch said.

“We were showing people their heart rate, and you could look at it — we were using it for calorimetry,” he told me. “But some users actually were looking at their heart rate when they weren’t working out, and noticed it was high. […]They would go talk to their doctor, and the doctor would find a heart issue, and we would start getting letters about this. We still get letters today about our work in the space, which is amazing. But some of those early letters were clueing us into ‘Wait, we could actually look for that ourselves in the background’.”

Apple then developed its high heart rate alert notifications, which can tell users when Apple Watch detects an unusually high heart rate that occurs when they aren’t moving around very much. High resting heart rates are good indicators of potential issues, and Apple also later added notifications for unusually low heart rates. This was all data that was already available to the user, but Apple saw that it could proactively provide it to users, providing the benefits already enjoyed by the most vigilant of all Apple Watch owners.