Hmm, maybe they are. I cycle a lot, which isn't the heaviest of sports. Gym honestly is a different league maybe. I heard people buying gym advertised headphones from Amazon, but they all fail at some point because they're too light (and shove off your head), or the paddings and internals are drowned in sweat. It seems like for gym, Bluetooth earphones are a better match. I do recommend the Bluedio TM for cycling, walking and running though.