Until a few minutes after it was published elsewhere on the web, Apple had a job listing up which suggested they were in search of physiologists for fitness and energy tests. This listing suggests that Apple is working more deeply than in the past on athletic programs - this in turn teasing the possibility that Apple could be getting closer to releasing a fitness-centered app of their own - tied to the iWatch, of course.
Apple's job listing suggests that the applicant(s) must have experience with exercise testing and a good understanding of physiological monitoring equipment as well as measurement techniques. Qualifications suggest, basically, that Apple needs someone with a vast understanding of how the body works and how to test it - and how to read the results.
"• Good understanding of physiological monitoring equipment, measurement techniques and interpretation of results
• Experience with indirect calorimetry to measure energy expenditure for a range of activities and environments
• Ability to design tests isolating the impact of various factors (activities, environments, individual subject differences, etc.) on the physiological effects being measured
• Experience with exercise testing – how to conduct, interpreting results, determining when to halt testing, etc."
These qualifications come from Apple via 9to5Mac where their screenshot of the job listing also suggests that the role also requires applicants to have "relevant knowledge to the design of products and their testing/validation through user studies."
This all seems to tie in well with recent rumors of a "Healthbook" software suite inside of iOS 8 as reported quite recently, also on the rumor side of the tracks. The iWatch is suggested to be set up with a vast collection of sensors according to the recent Healthbook wave of tips, making way for a next-generation operating system that has at least one app that can not only read what your body is doing, but can tell you if you need to take action as well.