I don't want to creep anybody out. But I was talking with an elderly relative about the days when most people died at home rather than in the hospital. She recalled as a young girl having to keep watch over her dying grandmother while her mother rested. Her mother instructed her that when grandmother's feet grew cold, the girl should come and get her mother because that was a signal that the old woman was near death. Makes you want to wear warm socks, doesn't it.
Death has a dramatic effect on the circulatory system too.
How this translated into our current usage has never been explained and it may be that the phrase has nothing to do with the proverb. One can imagine that he was fearful of losing all and his cold feet were as good an excuse as he could think of to help him get out of the game. The person stuck a toe in the water, found it freezing, and decided NOT to take the plunge because she got cold feet. This may be true, but if it is, it didn t happen in Ben Jonson s time, to the best of our knowledge. Cold feet in the sense of fear, originated as an American expression in the 1890s.