NOCTURNAL leg muscle cramping (NLMC) is a frequent complaint heard by physicians in all specialties, from patients of all age groups, though probably most commonly in the elderly. Such muscle cramping usually involves the calf muscles (gastrocnemius or soleus) or the small intrinsic muscles of the sole of the foot. Both muscle groups are functionally similar, and the following discussion is applicable to both. Leg cramps usually occur at night in bed and are precipitated by random muscle contraction or, more frequently, by voluntary stretching movements of the lower extremities. They are exquisitely painful and a cause for much distress and anxiety.
Nocturnal leg muscle cramping is to be sharply differentiated from leg cramps that occur from exercise such as walking or running. These can indicate an underlying pathologic process, such as the claudication of peripheral vascular insufficiency or the "pseudoclaudication" of radiculopathy, especially secondary to lumbar spinal stenosis. In
Weiner IH, Weiner HL. Nocturnal Leg Muscle Cramps. JAMA. 1980;244(20):2332-2333. doi:10.1001/jama.1980.03310200066033