I have a recurrent problem when riding in high humidity climate, either with hot or cool weather: after some hours riding, my nipples (in the chest, not in the wheel :o) get very sore from friction against the shirt's fabric.
It seems that it has to do with salty sweat, the waving-flag movement of the shirt fabric against the skin, and perhaps with cold causing nipple erection, further increasing the friction.
A more experient friend of mine has reported the same recurring problem, having even seen people bleeding from this.
So I ask if anyone else has suffered from this problem, and how I could expect to solve it. I am considering to take along some band-aids, but I think there could be some preventive measure before the band-aids be needed, in the first place.
Thanks for any insight!