So I went to St Louis last weekend to watch the Go! St Louis Marathon & Half-Marathon. If this seems super random, I should specify that Dan and his cousin were running the Half-Marathon, so I was mostly going for moral support and to hold the jackets.
I went to the Lincoln Marathon last summer, and a smaller race after that, so I'm not exactly a novice crowd member at these things, but this year I was shocked to not only finally notice a very unfortunate side effect of running long distances, but also find out why most major races offer free vaseline at the starting line. I will explain:
See this photo? Sorry for the blurriness, but it was raining horribly, so my camera lens had a bit of water on it.
The guy in the white shirt...look at the pinkish stripes on his shirt. Yes, his nipples are bleeding.
Apparently this is what happens if you run for a long period of time in a cotton or loose fitting shirt. The fabric shifts slightly for so many hours (2-3 hours for a decent half-marathon runner) that it begins to chaff. And after chaffing for a while...it begins to bleed.
So yeah, yet another reason that exercising is bad for you.