Low potassium is just one cause of nighttime leg cramps.
Nighttime leg cramps are defined as sudden, painful, involuntary contractions of the muscles of your legs during the night. Typically, nighttime leg cramps have no real cause and are simply a painful nuisance. There are times when these cramps may be associated with other conditions or disorders that may need treatment. If you are concerned about your nighttime leg cramping, consult your health care provider.