The pain in the calf in the middle of the night is severe and unbearable may have the following causes: 1. Vascular diseases: acute arterial embolism can occur in the arteries of the lower limbs. It is mostly seen in middle-aged and elderly male patients with history of smoking, hypertension, diabetes, etc. Patients show severe unbearable pain in the lower leg, abnormal sensation in the distal part of the lower leg, pale and cold, and inability to reach the dorsal foot artery. For treatment, emergency surgery can be performed in the acute stage. Or thrombolysis and anticoagulation can be performed. Then there is deep vein thrombosis in the lower extremity, which also presents with calf pain in the middle of the night. It is manifested as swelling of the lower leg. Generally need to carry out thrombolysis, anticoagulation and other treatment. 2, fatigue or cold factors: due to excessive exercise or cold stimulation of the lower limbs, there is a state of calf muscle tension at night, muscle twitching, and intense unbearable calf pain in the middle of the night. You can promote local muscle spasm relief through hot compress and massage. 3, hypocalcemia: caused by the lack of calcium in the body, mostly seen in pregnant women and elderly people with calcium deficiency. It can cause calf muscle cramps. The pain in the calf in the middle of the night can be severe and unbearable. It is necessary to use calcium supplementation drugs and eat more calcium food. 4, blood flow factors: for patients with varicose veins in legs or deep vein thrombosis, if they keep a certain posture for a long time when sleeping, the leg veins will be compressed and the reflux will be blocked, causing blood flow stagnation, and when the blood stagnation reaches a certain level, it will cause leg muscle cramps. You can go to the hospital for examination and symptomatic treatment.