While Apple supports the Nike+ activity monitor and has demonstrated a connected blood glucometer made by Lifescan at its iPhone 3G unveiling, its movement toward championing peripheral health devices for the iPhone has been decidedly limited to date. However, a recent patent application points to the a lot of activity on the connected health front inside the company's research and development teams: An Apple patent describes a couple of methods for using a wireless earbud to track a user's blood oxygen level, body temperature, heat flux and heart rate. The patent application notes that the earbud could use infrared photodetectors to monitor the user's biometrics. Here's a passage from the patent app:

"From infrared radiation in the user's ear, sensors... can detect minute temperature variations due to the user's heart beats. Heart rate can be calculated based on time between beats and the user's temperature can be set as the 'DC Component' (or average or median value) of the detected temperature distribution. Other sensors can also be used for tracking the same physiological metrics or different physiological metrics."

For blood oxygen levels, the system would require a light source and a photodetector to "detect the portion of such light that passes through the user's earlobe, the remaining light having been absorbed within the user's earlobe. From the relative absorption of these two wavelengths of light, the user's blood oxygen content can be calculated."

For more on the Apple patents, read this article from Apple Insider, which spotted the patents a few weeks ago.