Everyone has reported on it at this point, but the rumor originated with the Japanese newspaper Nikkei, which claimed:
The new watch-like wearable gear will run on this OS, which will be equipped with a centralized function to manage users' biometric information via smartphones. It is expected to hit the market in October.
Though the details of services have yet to be released, specs for the new product are being finalized, according to industry sources. It will likely use a curved organic light-emitting diode (OLED) touchscreen and collect health-related data, such as calorie consumption, sleep activity, blood glucose and blood oxygen levels. It will also allow users to read messages sent by smartphones.
Apple appears confident of the new product. According to a parts manufacturer, it plans monthly commercial output of about 3-5 million units, which exceeds the total global sales of watch-like devices last year. This confidence is backed by its partnerships with high-profile hospitals -- it has teamed up with the Mayo Clinic and the Cleveland Clinic, U.S. health institutes based in Minnesota and Ohio, respectively, to develop specific ways of analyzing the collected data and applying it to actual health management.
While some details mentioned above have been reported elsewhere, I have trouble believing that Apple will be launching a wearable in October.
Update: Re/Code is reporting a similar rumor from a second source. All they have is the launch date.
Sure, Apple did announce Healthkit earlier this week, and they also announced partnerships with the Mayo Clinic, Cleveland Clinic, and other hospitals, but that doesn't mean that Apple is necessarily going to launch a wearable this Fall.
My problem with this rumor (besides the Nikkei report being written in a tone which suggests that they don't have inside sources) is that there has been a marked lack of leaks. While over the past few months there have been multiple leaks related to the larger iPhones, I can't recall seeing any leaked components, specs, images, or other details related to a wearable.
The cardinal rule for Apple products is that you don't believe the rumors until after several hardware leaks prove the rumors true. That rule worked for the Retina iPad, the iPad Mini, and most new iPhone models, and in the case of Apple's rumored wearable I think it is only prudent to apply the same rule.
So tell me, have there been any leaks related to an Apple wearable?
I may have missed something, but I cannot recall any solid leaks. And without those leaks I'm just not convinced that new hardware is on the way.