Why do I feel weak all over?

General weakness can be caused by various factors, mainly including: 1. Lack of sleep: If you don't get enough sleep, your body and brain cannot adequately rest and recover, leading to various discomforts, including general weakness and listlessness. 2. Nutritional deficiency: Long-term poor eating habits can lead to nutritional deficiencies. Prolonged deficiency weakens the body's constitution, causing fatigue and lack of energy. 3. Excessive exercise: While moderate exercise is beneficial to health, overexertion can exhaust the body, leading to symptoms of fatigue, weakness, and low energy. 4. Medical conditions: Certain chronic diseases, such as liver disease, thyroid dysfunction, tuberculosis, tumors, and anemia, can also cause body weakness. If symptoms persist, prompt medical attention is recommended.