The reason why the body is always fatigued can be divided into physiological factors and pathological factors, the common ones are staying up late, excessive mental stress, high blood sugar, hypothyroidism, tumors and so on. Physiological factors, stay up late, mental stress, etc., the body is overworked, overuse of the brain, can lead to fatigue, fatigue, etc., can be adjusted through rest and relaxation, improve the mental status of the recovery, at the same time, pay attention to dietary laws, to ensure the supply of energy. Pathological factors, such as high blood sugar leading to impaired glucose utilization, hypothyroidism leading to reduced energy utilization and heat production, and excessive consumption of nutrients by tumors can lead to fatigue, which can be determined with the help of auxiliary tests such as blood glucose, thyroid function measurements, CT, and so on. If the body is always fatigued and accompanied by other discomforts, one should consult a doctor in time.