It was around July or so 50 years ago this year that I started playing the bass, my first was a Japanese EB-0 copy by Mateo, wish I still had it!
I'm not going to quit playing the bass, but there will come a time when I will not be able to play at the level needed, during the last set of a show in March my left hand cramped and froze up, it was frightening and quite difficult to continue.
I've had this happen on occasion. It's really scary when you're playing live. Sorry if I'm telling you something you already know, but make sure to stretch often and stay hydrated.