A yawn is often perceived as a simple sign of fatigue or boredom. However, this reflex as natural as universel could reveal much more on your hormonal health – especially on your cortisol level, the stress hormone. Explanations.
Yawning, an unsuspected hormonal indicator
Many research has attempted to unravel the mysteries of the yawn, without achieving a unique and final explanation. But a track particularly attracts the attention of researchers: that of the link between yawning and cortisol, this hormone which notably regulates stress, vigilance and metabolism.
This is explored by a study published in the International Journal of Medical Research, conducted by Simon Bn Thompson and Phil Bishop. Their hypothesis, called Thompson Cortisol Hypothesis, suggests that the levels of cortisol would rise during a yawn, just as they do during stress or great fatigue.
A revealing experience
In this study, 20 participants aged 18 to 53 were exposed to stimuli causing yawns. Saliva samples were collected before and after the yawn episodes in order to measure cortisol levels. In parallel, the researchers recorded muscle activity of the jaw using an electromyogram to analyze the rest and activation phases.
Result: in participants who have yawned, cortisol levels significantly increased after the yawn. This link was not observed in those who did not yawn, partially confirming the idea that yawning would be a physiological response to stress or increasing fatigue.
A hormonal mirror of our inner state
Clearly, yawn would not be a simple reflex of relaxation, but a tangible physiological sign of a temporary hormonal imbalance, in particular a peak of cortisol. The body would thus seek to regulate its internal temperature or to stimulate awakening via this mechanism.
Researchers even evoke the possibility of developing a diagnostic tool based on the detection of variations in cortisol during yawning, likely to help to identify certain neurological disorders early.
If you are building frequently for no obvious reason, this could reflect underlying stress or accumulated fatigue. It is not necessarily a serious symptom, but it probably deserves to be listened to. As the study by Simon Bn Thompson and Phil Bishop shows, our body often speaks stronger than our thoughts-still we have to know how to listen to it, even through a simple yawn.
