This condition is usually caused by two reasons: 1. Strenuous activities of the calf muscles before going to bed, such as outdoor basketball and other jumping movements, resulting in a slight strain on the calf muscles; or due to excessive walking, resulting in fatigue and strain on the calf muscles, which can form local inflammatory lesions, gradually appearing inflammatory edema, on the surrounding The peripheral nerves will be stimulated and the pain will appear. However, because the blood circulation is faster during activity, the metabolites produced can be metabolized in a timely and effective manner, so the painful symptoms of peripheral nerve stimulation are lighter or cannot be felt. However, after rest, the blood circulation slows down and the metabolites produced accumulate, so the pain is easily felt. After strenuous activity, the local energy and nutrient metabolism is faster and the consumption is greater, leading to the soreness of the calf. 2, is due to the cold at night, because after the cold will lead to the slowing of blood circulation, the resulting inflammatory metabolites will further accumulate, leading to a more obvious pain; and because the arterial blood supply will also decline after the cold, muscle tissue does not have normal energy and nutrient support, so the pain will appear. As the blood supply to the arteries decreases after the cold, the muscle tissues do not receive normal energy and nutritional support, so the soreness will appear.