

Apple not only unveiled the new iPhone last week. It also introduced a health and fitness data hub called HealthKit. (AP Photo/Marcio Jose Sanchez, File)

News about Apple's health and fitness data hub, HealthKit, got a bit lost last week amid splashier announcements on Apple Pay, the new iPhones and the Apple Watch. But Apple's move into the health data space makes the company a potentially powerful force in the growing world of health and fitness data.

The service isn't an app, per se, though its information will show up in the "Health" app on iPhones running iOS 8. HealthKit draws together health and fitness information pulled from other applications together -- the number of steps you've walked according to your pedometer app may show up alongside readings from your glucose meter, or weigh-ins from your smart scale. In all cases, Apple has said, users will be able to opt-in or out of having HealthKit collect that data in its central hub.

That, understandably, could make some users nervous about the security of that data -- especially in light of the recently leaked photos of celebrities that had been stored on Apple's iCloud.

The company has moved quickly to address privacy concerns that consumers might have about its new health product. Any information collected from health apps is stored, encrypted, on users' devices. If it does need to be transmitted to iCloud -- in the case of a backup, for example -- Apple will require the information to be encrypted. When it comes to third-party use of data, Apple has already told developers storing health and fitness data that they should not use iCloud, which does not meet the stringent federal requirements to comply with health privacy laws. (That also helps Apple neatly avoid the current debate over how medical data should be protected in the cloud.)

The company has also said that HealthKit data cannot be shared with data brokers or used for advertising. Developer guidelines for apps that access HealthKit also require that all such applications have a privacy policy, which pulls them under the watchful eye of the Federal Trade Commission.

Those measures drew some praise from Sen. Chuck Schumer, who has made the protection of health data one of his primary concerns. Schumer has, for example, criticized the fitness tracker Fitbit for not prohibiting the sale of data from its trackers to third parties. Fitbit has since changed its policies.

“Preventing the sale of personal information and requiring users to opt in to allow any sensitive data sharing are key components to any effective privacy policy, and Apple is doing the right thing by doing both," Schumer said in a statement. " Including provisions like these in privacy policies should be a no-brainer for tech companies.”

Privacy experts, however, said that while Apple may be being careful with health data, the very collection of data may sign users up for more than they bargained for. Joseph Turow, a privacy expert and professor at the University of Pennsylvania, said that users often don't understand how combining sets of benign-seeming data can identify them.

"I think people have to be wary," he said. "Who you are or how your personality is all can be inferred from little points of data. More activities will be looked at and this will have to be a social discussion we have."

The rise of fitness trackers and smart medical equipment is big business, with sales of at least $330 million as of the start of this year. But consumers often have to open several apps to track their data, because Apple does not allow apps to share information with each other. With HealthKit, Apple has the potential to knock down a lot of barriers within the industry, particularly when it comes to making it easy for users to see data collected by multiple apps in one place.

High-profile partnerships with organizations such as the Mayo Clinic and the electronic health record company Epic have made Apple's platform very attractive to developers, whose apps Apple needs to keep consumers coming back to Apple devices. "When they stepped up on stage with Epic and Mayo, they said to developer community that they will help you with access to these key health providers," said Morgan Reed, the executive director of the Association for Competitive Technology, an app developers trade group. "Those are doors that are rarely opened for us."