Feeling tired and weak all the time may be caused by physiological factors, but also some diseases, such as diabetes, anemia, hypothyroidism and cardiovascular disease. 1. Physiological factors: If the quality of sleep is not good or excessive fatigue, it is easy to appear the phenomenon of physical fatigue. If a woman is in the early stages of pregnancy, due to changes in hormone levels in the body, it may also lead to fatigue. 2. Disease factors (1) Diabetes: When the blood sugar in the body is too high, due to the body’s impaired utilization of sugar, it is easy to lead to fatigue. (2) Anemia: Anemia patients because of the lack of red blood cells, will make the muscles or nervous system lack of oxygen, resulting in fatigue. (3) Hypothyroidism: because of the reduced synthesis and secretion of thyroid hormones, the body’s metabolism will be slowed down, resulting in fatigue. (4) Cardiovascular diseases: If there are cardiovascular diseases such as high blood pressure and atherosclerosis, due to the damage of cardiovascular structure or abnormal function, it will lead to insufficient blood supply, which will make the organs and tissues lack of oxygen, and thus fatigue and weakness will appear. Old fatigue recommended to actively go to the regular hospital, can be clearly diagnosed, and then targeted treatment.