What causes a person to feel very tired and fatigued?

Generally, feelings of extreme tiredness or fatigue may be caused by insufficient sleep, overexertion, iron-deficiency anemia, hypothyroidism, chronic fatigue syndrome, and other conditions. It is recommended to seek medical attention promptly, identify the underlying cause, and receive appropriate treatment under a doctor's guidance. Specific causes are analyzed as follows:

1. Insufficient Sleep: Long-term staying up late or poor sleep quality prevents the body from getting adequate rest and restoring energy, leading to fatigue. Adjust sleep schedules, ensure 7–8 hours of sleep each night, avoid using electronic devices before bedtime, and create a quiet, comfortable sleeping environment to improve sleep quality.

2. Overexertion: Prolonged high-intensity work or frequent physical labor excessively consumes energy and keeps muscles in constant tension, resulting in fatigue. Plan work and rest periods reasonably, avoid working continuously for long durations, take a 10–15 minute break every 1–2 hours, and engage in light activities such as walking or stretching to relieve physical fatigue.

3. Iron-Deficiency Anemia: Inadequate iron intake or excessive iron loss reduces hemoglobin levels, impairing oxygen transport and causing tissue hypoxia, which leads to fatigue, often accompanied by pale complexion and dizziness. Patients can take iron supplements such as ferrous sulfate tablets, ferrous succinate tablets, or ferrous fumarate granules as directed by a physician.

4. Hypothyroidism: Insufficient production of thyroid hormones slows down metabolism and reduces energy production, causing persistent fatigue, along with symptoms like cold intolerance, weakness, and weight gain. Under medical supervision, patients may take medications such as levothyroxine sodium tablets, thyroid tablets, or L-thyroxine sodium tablets to supplement thyroid hormones and regulate metabolism.

5. Chronic Fatigue Syndrome: Triggered by long-term stress, immune system dysfunction, and other factors, this condition is characterized by fatigue lasting more than six months that does not improve with rest, often accompanied by memory decline and muscle pain. Patients should follow medical advice to use medications such as amitriptyline hydrochloride tablets, fluoxetine hydrochloride capsules, or vitamin B12 tablets to alleviate symptoms.

Maintain a balanced diet in daily life, consuming more protein- and vitamin-rich foods to provide the body with sufficient energy. Engage in moderate exercise such as jogging or yoga to strengthen physical health, improve bodily functions, and reduce the occurrence of fatigue.