Leg cramps (Charley Horse) are painful sensations of tightness in muscles of the leg, especially, in the muscles of the calf, foot and thigh. Nocturnal leg cramps are cramps that occur at night when a person is sleeping.
These cramps are not life-threatening and have, generally, not been linked with any medical condition but are very painful and can lead to sleep disturbances. The muscle remains in a cramped and contracted position for few seconds to minutes which accounts for the intensity of the pain. Although anyone can be affected by nocturnal leg cramps, elderly people and pregnant women are affected more by nocturnal leg cramps due to poor blood circulation in the limbs.