“Calf cramps can be caused by a variety of factors. Calf cramps during sleep may be related to excessive exercise during the day, and the calf muscles may spasm involuntarily at rest, resulting in calf cramps, which can usually be relieved after stretching the local muscles.
In addition, calf cramps may also be caused by poor blood circulation due to local coldness in the calf caused by inattention to warmth while sleeping.