Calf soreness at night may be caused by physiological factors such as prolonged standing and excessive exercise, or it may be caused by pathologic factors such as lumbar disc herniation, pyriformis syndrome and varicose veins of the lower extremities. 1. Physiological factors: standing for a long time during the day is likely to affect the blood circulation of the lower limbs, slowing down the blood flow, which can cause calf soreness. Or a lot of exercise during the day, stimulating the body to produce more metabolic products, lactic acid accumulation, causing symptoms of calf soreness. 2. Lumbar intervertebral disc herniation: due to the herniated intervertebral disc compression of the nerve root, can lead to lumbago and one side of the lower limbs of the pain and numbness, if the work during the day or weight-bearing, can lead to the nerve compression symptoms aggravate the appearance of the calf to the night soreness obvious feeling. 3. Piriformis syndrome: it is a nerve compression disease of lower limb pain, numbness and weakening of lower limb muscle power caused by compression of sciatic nerve in the area of piriformis muscle, and it can show the symptom of intensified calf pain at night after strenuous activities during the day. 4. Varicose veins of the lower limbs: the elderly, pregnant women, sedentary, long standing and other groups of people prone to varicose veins of the lower limbs, can appear in the lower limbs of the swelling, pain and other symptoms. Calf soreness at night can also be seen in other reasons, patients should consult a doctor in a timely manner, in the diagnosis of a professional doctor and under the guidance of targeted treatment.