We know that fitness trackers are a thing, and headphones are certainly a huge thing, but are fitness-tracking headphones a thing?

Sony wants to believe this is a new category, which is why it debuted the Smart B-Trainer back in January. It wasn’t the first manufacturer to build fitness-tracking tech into headphones (that was probably LG, a year earlier), but it built on something Sony had been doing for a while: Headphones that did a lot more than just relay sound.

Wireless headphones came in the late 2000s. The Walkman headphones, which include storage for music, debuted in 2011 and Sony made an underwater version — yes, underwater, not just waterproof — in 2013.

So fitness tracking? Not such a big leap. Besides 16GB of music storage, the Smart B-Trainer headphones include sensors for measuring heart rate and pace, and they’re still fairly lightweight. The company began selling the device in Japan earlier this year, and it’s coming to the U.S. this fall.

Checking them out for the first time at a Sony press demo, I thought the headphones were surprisingly comfortable. I picked the pink ones (sorry, rose gold); the B-Trainer also comes in neon green and black. The earphones slip on intuitively, and they don’t feel anywhere near as bulky as they look. Wisely, Sony made the connecting cable between the two earpieces not entirely slack, but it’s bendy enough for running around.

Spotify Running grabbed headlines in the spring for offering a service that adjusts music based on your pace, and Sony’s headphones can do even better: The B-Trainer can select music based on your heart rate.

Here’s Sony’s Smart B-Trainer in the flesh. pic.twitter.com/GKXNFf64Bj

— Pete Pachal (@petepachal) September 15, 2015

To check the feature out, I began a training run through the accompanying app. After scanning my resting heart rate (71, if you’re scoring), it picked a pace it thought I could handle, targeting between 95-111 beats per minute (bpm). As it started, it immediately hit me with some aggressive hip-hop to get me moving.

I climbed on the treadmill in the demo area and started walking briskly. According to the B-Trainer, my heart rate quickly jumped to 98 bpm. The music switched to something a little more moderate, Bruce Springsteen’s “Born to Run” (natch). Presumably, if I had pushed too hard, it would try to slow me down with some light jazz.

Because the music is stored right on the gadget, you don’t need to bring your phone with you, but if you do, you can check out the screen whenever you want to see where your heart rate is at. The UI is very visual: Your bpm is right in the middle of a circle, and your target range is clearly marked with a red arc on the edge. Of course, it updates in real time.

The app that accompanies the B-Trainer has a lot more features than pace tracking and real-time music selection. According to Sony, the Smart B-Trainer app can even plan out a whole training regimen for you; just tell it your goal and the date you intend to achieve it (say, a half marathon 3 months out), and it’ll figure out all your training sessions, based your goal, profile and history. However, extensive training goals like marathons are considered “premium,” so they’ll probably require an in-app purchase.

But the best thing to recommend about the Smart B-Trainer may be its broader utility: Smartwatches have many of the same features, but their downside is they require you to wear another gadget. For working out, you’re going to wear headphones anyway. Why not put the brains in there? For those who gave up wearing watches and aren’t looking to go back, Sony’s Smart B-Trainer could be a compelling way to smarten up your workouts.

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