In the morning, there are three main situations: 1, during the night sleep there is a cold calf area, cold will lead to slow blood circulation, arterial blood supply decreases, the calf muscle soft tissue does not get enough electrolytes, energy and nutritional support will appear sore, weak feeling; In addition, due to the slowing of venous return, will lead to the local production of lactic acid and other metabolic products appear 2.It is because the muscles in the calf area are not fully relaxed during sleep at night, which will lead to continuous muscle fatigue and strain, so there will be a feeling of weakness. 3.It is because before going to sleep, the calf area is more active, such as strenuous exercise or long distance walking, walking too much, resulting in frequent calf muscle in This will produce a large consumption of nutrients, energy and electrolytes around the calves; and because of the cold and slowed blood circulation in the calves, it will also lead to the accumulation of local inflammation and metabolism or a decrease in arterial blood supply, resulting in the gradual aggravation of weakness.