As rumored, Apple has announced its iOS 8 health initiative during the WWDC 2014 keynote. The new Health app will work with a developer API bundle called HealthKit. In iOS 8, apps will be able to report your health data to a centralized location, allowing you to see all the information and stats from different apps all in the same area. Further, you'll be able to choose if you'd like to share health data from one app to another.
Apple announced that Nike and the Mayo Clinic are two of the first to be working on HealthKit integration, while also picturing a Withings blood pressure monitor. Not much more has been announced about the new Health app for iOS 8 yet, but we're sure we will hear more about it closer to the release of iOS 8 release.