Suggest Treatment For Severe Muscle Cramps On The Legs

I am 67 years old female and have been getting severe muscle cramping in the legs below the knees, this happens every Thursday for some reason. Hot pad on the souls of my feet helps with the pain and the cramping, also Tums, and gravel ( dimenhydrinate) help a little. The pain is quite intense 7 out of 10( 10 being the highest in pain). This can last from 10min. to 40min. tonight s attac has been the longest and strongest.