Apple is apparently working on a new activity band for Apple Watch that would be made of stretchable fabric, and conduct health measurements including blood pressure. That, at least, is what the company’s new patent shows.

The patent, titled “Fabric-Based Items with Stretchable Bands,” also describes how the band would be able to get its power wirelessly from another device.

“The stretchable band may be formed from a ring-shaped strip of stretchable fabric having an opening configured to fit around a body part of a user,” the filing says. “Circuitry may be coupled to strands of material in the stretchable band.”

“The circuitry may include sensor circuitry for making measurements on the body part such as electrocardiogram measurements, blood pressure measurements, and respiration rate measurements. A coil formed from conductive strands in the fabric-based item may be used by wireless power receiving circuitry in the fabric-based item to receive the wireless power.”

Beyond Apple Watch, the company envisions the use of such a sensor-laden stretchable band in a head band or other wearable item that includes elastic fabric, yoga clothing or other athletic attire, an arm band, an elastic belt, a sock, a glove, and so on.

The filing also talks about materials, including nylon and spandex, which would be used in the production of such a band.

Of course, just because a patent has been filed doesn’t mean Apple will actually go and make something. Many patents lead nowhere, but who knows — perhaps some future Apple Watch gets this sort of band. Or perhaps the iPhone maker expands its reach into the sports equipment market. We’ll be watching this space…