Charleyhorses

So, I'm wondering if this can be a symptom of something, because it has never happened to me like this before, and yet it rings a faint bell in my memory, as though I've heard of it. You see, lately, I've had quite a lot of charleyhorses gripping the muscles of my calves -- can't actually remember whether it's always the same leg, or both legs. Anyway, stretching does not always help and it's fairly annoying and kind of painful, but no serious big deal. But last night I had an ENORMOUS charleyhorse, a huge, crippling, dreadfully painful charleyhorse that had my left leg twisted up like a pretzel. I was unable to get it to let go, and although I sat up in bed, I couldn't stand up at first, because for a minute or two I was unable to put any weight on it. When I could, I went lurching through the house, limping like a pirate on his wooden leg, and crashing into the frame of each doorway I passed through.

When I returned to bed, I dreamed a complicated and distressing dream which I now cannot remember very well, but which was all about the crippled-up leg I had! So it had re-cramped itself in my sleep. And then this morning when I woke, it was painful and untrustworthy.

'Course, it's fine now, only a little bit sore, but more like I was hiking yesterday, not like the aftermath of a charleyhorse.

So, is this a result of being old? Or fat? Or a stroke victim? Or a gallbladder patient? Or WHAT?