Apple has been granted a patent on earphones which are able to monitor your temperature, heart rate and perspiration.
The illustrations for health tracking system show the new sensors hidden inside familiar earbuds, or else contained in an external but connected piece of hardware, rather than relying on any kind of external band.
Appleinsider speculates that the tracking could happen thanks to a metal ring around the outside of the earbud.
Needless to say, the idea is nothing new - not least because Apple first applied for the patent in 2007 and other companies have announced or attempted to make similar products in the years since.
Indeed, neither does the grant of the patent mean that Apple will definitely make such a system - though it does lend further weight to the idea that the company is strongly interested in health tracking as a future for its mobile devices.
Apple has recently made a number of big hires from the health tracking, wearable tech and data metrics industries, and speculation about a possible iWatch wearable device coming as a complement to the iPhone are stronger than ever.
But we'll have to wait and see if anything comes of it. Apple files hundreds of patents each year, and most never make it into products.