Yawning and airway physiology: a scoping review and novel hypothesis.

Background and purposeYawning is a stereotypical complex muscular movement and is commonly executed by most vertebrates. In seconds, the entire airway is fully dilated and surrounding muscles are powerfully stretched, most prominently around the pharynx. To date, yawning has been rarely studied, and as of yet there is no consensus on its main function.Material and methodsTo investigate a mechanical airway function for yawning, a literature search was conducted to relate the frequency of yawning and obstructive airway conditions.ResultsThe results show that changes in obstructive airway conditions and alteration of the frequency of yawning are temporally related.InterpretationThese relationships, however, cannot be interpreted as causal, nor can they be extrapolated to explain the function of yawning. Yet airway management and yawning share many physiological characteristics. We therefore propose a novel hypotheses: yawning plays a significant role in airway physiology by muscle repositioning and widening the airway lumen, thereby securing long-term oxygenation.