Google Fit, a health data aggregation service, is expected to launch at the Google I/O conference in San Francisco next week. The service will compete with Apple’s new HealthKit app framework, which launched last week. It will also compete with Samsung’s Sami, a similar biometric data platform. Google Fit aims to store data from wearable activity tracking devices — including Fitbit, Jawbone UP and Nike FuelBand — along with the related smartphone apps.

Google is expected to announce partnerships with wearable device makers at the conference June 25-26.

Fitbit, Jawbone UP and Nike Fuelband accounted for 97 percent of the digital fitness device market revenue last year.

“One source with knowledge of Google’s plans said Google Fit would allow a wearable device that measures data like steps or heart rate to interface with Google’s cloud-based services, and become part of the Google Fit ecosystem,” reports Forbes.

Complications concerning Google Fit include privacy and how to provide valuable feedback without interfering with FDA-regulated diagnoses.

Google launched a similar service in 2008 for medical records. “Google Health never took off because consumers actually don’t want to aggregate their data,” says Derek Newell, CEO of digital health care platform Jiff. “They haven’t wanted to. What they want is information. They want meaning, rewards and a feedback loop.”

Forbes speculates that Google may want Google Fit to tie in with Android Wear.