Hello Dear,
In addition to the more common causes of cramps - muscle overuse, dehydration, injury and strain - muscle cramps in the legs can result from:
Inadequate blood supply: Narrowing of the arteries that deliver blood to the legs (arteriosclerosis of the extremities) can produce cramps in the legs and feet while exercising. These cramps go away within a few minutes after stopping.
Nerve compression: Compression of nerves in the spine (lumbar canal stenosis) can produce pain and cramping in the legs. The pain usually worsens if one walks for a longer time. Walking in a slightly flexed position may improve symptoms.
Potassium loss: Some diuretic medications prescribed for high blood pressure cause loss of potassium. Potassium is necessary for proper nerve function and muscle contraction.
You should consult a neurologist and get the cause evaluated.
Best