Cable oxidation occurs because of moisture, so when you sweat on the cable all sorts of bad things can happen, and it depends on each person/cable as both have various compositions the react differently. For example, my SM3 cable is starting to harden where I was sweating on it but my M6 cable never hardened when I used to use that long ago.
As far as moisture, I believe BAs are more susceptible to damage from moisture as once moister gets in the sound tube/driver it is much more difficult to have it dry out due to the small size and lack of air flow. The do make hearing aid dryers that I would recommend using with your expensive custom IEMs, especially if you workout with them!












