Apple's mission to centralize your health data is already receiving strong support from hospitals and medical clinics, especially when compared to similar efforts from Google and Samsung. Now the list of early partners has grown to include Cedars-Sinai Medical Center in Los Angeles. According to Bloomberg, the hospital just flipped on support for HealthKit in its patient records systems over the weekend, instantly giving doctors access to synchronized data from hundreds of health and fitness apps that support Apple's platform. "Rather than turn it on as sort of an opt-in, we’ve basically enabled it for all of our patients," Darren Dworkin, the hospital's chief information officer, told Bloomberg. That could enable over 80,000 patients to give Cedars-Sinai doctors a deeper peek into their health.

With a user's permission, iOS 8 allows third-party apps to exchange and update health details that, when paired with more traditional medical tests, can provide a more comprehensive portrait of someone's personal health. At WWDC 2014, Apple software VP Craig Federighi said HealthKit's purpose is to build "a composite profile of your activity and health." It puts all of that data in one place so it's easily accessible to third-party apps and medical professionals.

Your HealthKit profile includes basics like height, weight, and the amount of steps you take each day. But for patients using optional hardware accessories, HealthKit can also provide information on things like heart rate, blood pressure, body fat percentage, glucose levels, and more. Users can control which third-party apps are allowed to see and modify this data.

"This is just another set of data that we’re confident our physicians will take into account as they make clinical and medical judgments," said Dowrkin. "We don’t really, fully know and understand how patients will want to use this and we’re going to basically stand ready to learn by what will happen." And if patients want nothing to do with Apple or HealthKit, Dworkin says the solution is easy enough: ignore it entirely. "The opt-out is just don’t use it."