Weakness, sore legs and feet are usually caused by the following factors: 1. The most common factor is the initial stage of the cold, whether it is a bacterial cold or a viral cold, or other atypical pathogenic cold, there will be clinical symptoms and manifestations of weakness, sore legs and feet. 2. Weakness, sore legs and feet are also seen in endocrine metabolic diseases, such as ion disorders of hypokalemia and hyponatremia. 3. When blood sugar is lower than 3.9mmol/L, the above symptoms will appear, but also accompanied by dizziness, palpitations, sweating, hand tremors and other clinical symptoms and performance. 4, also seen in the early stage of heat stroke, such as heat stroke when heat cramps, heat exhaustion and pyrexia, there will be no energy around the body, legs and feet of the clinical situation. 5, such as excessive exercise or exercise mode The above clinical manifestations may also occur if excessive exercise or incorrect exercise methods lead to excessive accumulation of lactic acid in the body.