I just had a conversation with some friends about the invincibility of youth to cold- what is it about being young that allows one to ignore the cold? For example, when I was in college, I wouldn't think twice about leaving my coat at home in January (in Minnesota) if I was going out for the night. Now, I make sure I have my winter coat, arctic hat and gloves, heavy boots, etc, and I still shiver. Sure there is a bit of hubris to it, but really, there has to be something else!