Yawning may be caused by physiological reasons, insufficient blood supply to cerebral arteries and hypoglycemia. 1. Physiological reasons, if the recent period of time due to work and life causes overwork, regular lack of sleep or stay up late, will lead to body fatigue, no spirit, and then the symptoms of yawning, can be improved through rest. 2. Insufficient blood supply to the cerebral arteries, if the elderly, due to the aging of the organism, it will lead to decreased elasticity of blood vessels, atherosclerotic disease or plaque and embolism may occur, the blood flow is reduced after the brain is hypoxic, the organism will be compensated for the intake of oxygen through yawning. 3. Hypoglycemia, if nutritional intake is insufficient, insufficient energy, will not be enough to supply to the normal functioning of the organism, which affects the state of mind, depression, can also be manifested by rest. If there is a lack of energy, it will not be enough for the normal functioning of the body, which in turn affects the mental state. If yawning occurs for a long time, it is recommended to consult a doctor in time to clarify the cause and then timely treatment.