The common clinical causes of yawning are environmental factors, mental factors and cardiovascular diseases. 1. Environmental factors: If you are in a closed environment for a long time, it is easy to cause the body to lack of oxygen, which will lead to the symptoms of yawning. In this case, it is recommended to pay attention to open windows and improve the surrounding environment, but also to walk outdoors and breathe fresh air. 2. Mental factors: If the mental stress is too high, the symptoms of frequent yawning may also occur, accompanied by irritability, irritability, anxiety, poor quality of sleep, sleepiness, insomnia and so on. 3. Cardiovascular and cerebrovascular diseases: this condition is mostly seen in the middle-aged and elderly people, if they suffer from arteriosclerosis, hypertension, heart disease and other cardiovascular and cerebrovascular diseases, which will cause the elasticity of the blood vessel wall to decrease, and the contraction function of the heart is weakened and the phenomenon of cerebral hypoxia occurs, which will lead to neurological dysfunction, and the clinical manifestations of frequent yawning, fatigue, and so on. If the above situation exists, it is recommended to consult a doctor as soon as possible for a clear diagnosis and further symptomatic treatment.