Born to yawn? Cortisol linked to yawning: a new hypothesis.

Yawning has become an interesting and curious scientific conundrum. Links between several neurological disorders can be found through the commonality of yawning episodes and contagious yawning. However, the reasons why we yawn are uncertain. Cortisol levels are known to rise during stress and fatigue; yawning may occur when we are under stress or tired. We do not know whether cortisol levels fluctuate during yawning. Potentially, yawning and cortisol levels may provide a valuable diagnostic tool and warning of untoward underlying neurological problems. A new hypothesis is proposed that links cortisol levels with yawning episodes.