Feeling tired 1 month after surgery for sigmoid colon cancer may be related to normal reaction after surgery, body weakness, anemia, insufficient nutrition intake and so on. 1. Normal postoperative reaction: sigmoid colon cancer is a major surgery, which will cause certain damage to the body and it takes some time for the body to recover, so it is normal to feel tired all the time. 2. Weakness: Due to the erosion of body by cancer cells, patients themselves will have the phenomenon of weakness, plus the influence of surgery, which makes the patient’s body even weaker, so the patient will have the feeling of tiredness. 3. Anemia: if there is heavy bleeding during the operation due to various factors, the patient may suffer from anemia, which may lead to drowsiness and fatigue of the whole body. 4. Inadequate nutritional intake: If the patient does not have enough nutrients after the surgery due to physical discomfort and lack of appetite, it will also cause symptoms of tiredness. It is recommended that patients seek timely medical attention to understand their condition and give reasonable adjustments or treatment. During the recovery period, pay attention to the balanced intake of nutrients, usually go out to move the body more, sunbathing, etc., is conducive to the recovery of the body.