HealthKit, a new feature of Apple's iOS 8, will let apps share health and activity information and send it to doctors.

The new version of iOS, announced at Apple's World Wide Developers Conference on Monday, will also let developers share features across apps, such as bringing a language translation function into the Safari browser. Other new features in iOS 8 include predictive typing suggestions, recording voice messages in the Messages app, and developers' ability to sell bundles of apps.

HealthKit was the biggest complete addition to iOS in what Apple called a major step forward for the mobile OS.

"iOS 8 is a giant release," CEO Tim Cook told the approximately 6,000 developers in the audience at WWDC in San Francisco. The new OS is available in beta testing now and will be generally released in the fall of this year, Apple said.

With HealthKit, Apple aims to bring together what have been siloed bits of information about health and activity in order to create an overall profile of a user's health.

Today, for example, activity level, heart rate and weight information are typically in separate apps, as are data about chronic health conditions such as diabetes and high blood pressure, said Craig Federighi, senior vice president of software engineering. Using an app that comes with HealthKit, called Health, users can see all the health and activity information their phone collects in one place, he said.

HealthKit will also let one application share information with another, with the user controlling what data is shared with which applications. For example, data such as heart rate and weight could be shared with a fitness app from Nike, which is working on using HealthKit, Federighi said.

Users will also be able to allow applications to share such information with apps from health care providers, who can compare readings with the ranges prescribed that patient. "If not, it can contact the hospital proactively, notify a doctor, and that doctor can reach back to that patient, providing more timely care," Federighi said. Apple has partnered with the Mayo Clinic in developing one such app. Epic Systems, which makes software for medical centers, is also working on integration with HealthKit.

Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is [email protected]