What causes frequent yawning?

Frequent yawning may have various causes. 1) It could be due to physical fatigue or lack of sleep; when the body or brain is tired, yawning can help refresh the mind and restore alertness. 2) Yawning may also relate to insufficient oxygen supply—for example, after prolonged time in a closed environment or poor air quality—where the body attempts to increase oxygen intake through yawning. 3) Certain medical conditions, such as obstructive sleep apnea syndrome or rhinitis, may also lead to frequent yawning, as these disorders can affect breathing and sleep quality. 4) Psychological factors like stress and anxiety may also increase yawning frequency, since emotional tension can disrupt normal bodily regulation. If excessive yawning persists and is accompanied by other symptoms, it is advisable to seek timely medical evaluation.