What is the low ambient temperature when shirtless running becomes unadvisable? I find that whenever I run in a shirt for, say, 1:20, I get problems like chafed nipples. So, for now, I run without a shirt. But the weather is getting colder.
I'm sure it's an individual kind of thing. With no wind involved, I can (and do) run shirtless down to about 45-50 degrees F. Below that I wear layer(s) of shirts/sweatshirts thru the winter to keep suitably warm and of course take steps to avoid chafing.
