Feeling weak is not necessarily due to ischemia, but may also be caused by long-term overwork, depression, cerebrovascular lesions and other reasons. 1. Long-term overwork: If you work late at night for a long time, do not have enough time to rest, and are always in a state of overwork, resulting in the body and brain not getting enough rest, it will cause weakness. 2. Depression: Depression is a psychological disorder that mainly manifests itself in low mood, and there will be obvious fatigue, easy to get tired, and you will feel weak to do anything. 3. Cerebrovascular lesions: Cerebrovascular lesions lead to atherosclerosis of blood vessels in the brain, narrowing of the lumen of blood vessels and thickening of blood vessel walls, which results in poor blood flow, ischemia and hypoxia of the brain, which may make the patient feel weak. Feeling weak may also be hypokalemia, hypothyroidism and other conditions, it is recommended to consult a doctor in time to clarify the cause of the disease and receive treatment under the guidance of the doctor to avoid delay.