so now 3 years after this @gkleiner1 post I found another possibility. I'm going to look IT up. I've tried extra magnesium which I found someone had said worked and I've tried even extra water which puts me at over 1 liter per day of water. That one worked for about 4 nights but now I am back to having the foot, ankle and low calf and shin cramping at night. I wake up about 1.5 hrs after retiring to bed, then about every hour afterwards with cramping. There has to be something. My friend told me that a coach for a high school tennis group gives packets of mustard to the player when he has cramps. My friend said she tried it and it did work. I can't bear to try it. There is no way I can squirt an entire packet of mustard into my mouth and then swallow it. Does anyone have a cause or remedy?