I'm using a carbon 90s-era Trek (which I bought specifically for the purpose; upgraded the drivetrain with Microshift parts to bring it into the 21st century) on my stationary, and it definitely looks the worse for it. I do keep a sweat guard over the top tube and stem, but the finish on the cranks is rough, the bottle-cage "braze ons" are corroded, and sweat nearly seized the seatpost (my wife and I both use it, so it gets raised/lowered frequently). I wound up putting a bit of aluminum anti-seize paste on it.