Apple's Next Big Focus: Your Health

Apple Inc. AAPL +0.87% has jolted many industries over the years, from recorded music to mobile phones. Now, it is charging into health and fitness, hoping to bring order to a fragmented mess of wearable devices and scattered data.

Its entry is stirring enthusiasm among entrepreneurs and health providers. But Apple will have to overcome regulatory and privacy challenges and consumer indifference.

Apple on Tuesday is expected to unveil a smartwatch embedded with more than 10 sensors to monitor health and fitness signs, according to people familiar with the matter. Apple declined to comment.

"When Apple does it, consumers perceive it as more mainstream," said Ari Caroline, chief analytics officer for Memorial Sloan Kettering Cancer Center in New York, one of several health-care institutions building apps to work with Apple's offerings. Others include the big health insurer Kaiser Permanente and the Mayo Clinic. With Apple's device, Mr. Caroline said, "people will have all the hardware they need to make the monitoring possible."

Apple already declared its intentions with some big-name hires and its HealthKit, a data repository created by Apple to work with iOS apps, storing information collected by various devices. HealthKit can channel the information to doctors, app developers and others, with a user's permission.HealthKit will work with apps in Apple's next mobile operating system, iOS 8, due out later this month. The new operating system will also include an app called Health—a dashboard for health and fitness information such as heart rate, calories burned, blood sugar and cholesterol, as well as lab results and medications.

So far, interest in digital health has been confined mainly to athletic people who are motivated to upload personal fitness information into apps and track their daily activity through devices.

People "just don't want to engage with a health app the way they'd engage with an Instagram or a Facebook, FB +1.72% " said Dr. Joseph Kvedar, director of the Center for Connected Health, an affiliate of Harvard Medical School. "There's a lot of foaming at the mouth and market estimates…the part that is missing in mobile health is the part that convinces people they have to use it."

The lack of enthusiasm has felled prior efforts by tech companies. In 2008, Google Inc. GOOGL +0.78% launched Google Health, a portal where consumers could upload health records and share them with insurers and providers. The search giant closed the portal three years later. Microsoft Corp.'s MSFT +1.44% Health Vault, another attempt to house and share medical data, hasn't gained much traction.

Apple may benefit from better timing. When Google launched its portal, smartphones weren't as prevalent as they are now and health apps were still new. Consumers also have more incentive to monitor their health because they are shouldering more of the burden of health-care costs. What's more, a growing number of companies are offering financial rewards for people to adopt healthy behaviors or track things like weight or activity.

Many hospitals and insurers are intrigued by the possibilities of Apple's smartwatch and HealthKit. John Halamka, chief information officer of Beth Israel Deaconess Medical Center in Boston, said doctors could remotely monitor patients after a procedure for signs of complications. He said hospitals can also save money by detecting problems early because the Affordable Care Act penalizes hospitals that have too many readmissions.

To gain widespread adoption, Apple will need to convince users that their health information is safe, a task that became more difficult after hackers posted nude pictures of celebrities that had been stored in Apple's iCloud service.

Even before the hacks, Apple was taking measures to protect privacy. The company said it wouldn't allow app developers to store health data in iCloud—and wouldn't allow companies that share information with HealthKit to use it for advertising. To steer clear of regulators, Apple also said apps using data from HealthKit can't provide diagnoses or treatment advice.

Apple wants to support and bring order to what is now a small and unruly market, but questions loom over whether the company will have the capability to police a growing number of apps.

Market research firm NPD estimated that the U.S. digital-fitness market, including sales of wearable devices such as the Fitbit and Jawbone UP, totaled more than $330 million last year.

By comparison, Apple's shrinking iPod business generated $442 million in the April-June quarter—the equivalent of less than two days of world-wide iPhone sales. As of December 2013, there were roughly 40,000 health apps being marketed, according to Healthcare Information and Management Systems Society, a nonprofit for the health industry.

"Up to now, the information gathered by those applications lives in silos," said Apple Senior Vice President Craig Federighi at a company conference in June, where he introduced HealthKit.

To support its initiative, Apple has hired engineers and scientists from medical-device and bio-sensing companies.

The company has been working on ways to use advanced sensors to track a person's blood pressure, body temperature, glucose and hydration levels, these people said.

The high-profile hires include Michael O'Reilly, former chief medical officer of Masimo Corp. MASI +0.05% , which makes a finger-sized device to measure oxygen in the blood without drawing blood.