When I was training for marathons and running 5-8 miles per day and 15-20 miles on Sunday nights, I wore one of those huge black armored watches with all the functions on it. The watch was somewhat loose on my wrist and made a gentle tapping on on the wrist right where the nerve is. After four or five years of this, there was a slow progressive loss of feeling in those two fingers. Magically, the feeling came back after a few weeks of time when I quit wearing a watch while running.
