Positive Health Online

I am not a great believer in contagion in general but I'll make an exception for yawning. Although not a disease, yawning is definitely contagious, i.e. communicable, infectious, quickly affecting others.

And just by reading this article you run the risk of being overcome by a fit of yawning. All mammals practise it; some fish as well (without even the risk of drowning!). But, according to Bertrand Deputte, a primatologist at the CNRS (national organization for scientific research) of Paimpol in Brittany, only humans are able to 'catch a yawn'.[1] Even monkeys, our close relatives, don't seem to have elevated the art of yawning to a catching point.

The word yawn is linked to 'gap' and 'gape' from old Norse gapa 'open the mouth'. The mouth is indeed open, wide open, when we yawn and that's why it's better to do it without any yawing of the jaw lest we unhinge it. FM Alexander observed that "there are very few men who, when told to open the mouth, will not throw the head back with the idea, as it were, of lifting the upper jaw away from the lower".[2] This misuse is even more frequent when the opening of the mouth is caused by the yawn reflex. Yawn, as an intransitive verb, is defined by The New Shorter Oxford Dictionary as "open the mouth wide and inhale (silently or audibly), as an involuntary reflex when sleepy or bored". I would question this definition since, quite apart from the fact that 'an involuntary reflex' is rather redundant (a reflex is 'an automatic or involuntary activity...'), yawning does not seem to be related to boredom or sleepiness.

If boredom and/or sleepiness are not what trigger yawning, why do we do it at all? Is it to display our soft-palate, glottis, teeth, cavities and all? Or is it to give a good stretch to our mandible? When tired we breath shallowly and less frequently, and it is commonly thought that yawning is a mechanism that enables us to fill up our lungs with oxygen and thereby invigorate our brains. This explanation has been tested in the lab by Robert Provine, a psychologist at the University of Maryland, Baltimore County, and has been proved to be a myth.[3] In most mammals yawning is restricted to the time of waking up.

But in primates it is a bit more socialized: they "often yawn after an activity which increases their vigilance, such as a fight or a copulation", says Bertrand Deputte. But Ronald Baenninger, a psychologist at Temple University in Philadelphia, discovered that yawning is common just before periods of activity.[4] He thinks that "we yawn in situations where there is nothing to stimulate us, but it would be bad to lose the level of arousal". The findings of Provine support this hypothesis. So yawning could be a reflex designed to prepare our brains for action or for change. If that is the case and if, as Shakespeare asserts, "readiness is all", yawning is not a trivial affair and we should not be ashamed of doing it and refrain it for politeness' sake. Yawn to your heart's content.

A warning though: As with all good things, yawning is best done in moderation. And yawning can also be a symptom, warning us that all is not well with our health. For example, frequent yawning can be a sign of hyperventilation. According to Provine, schizophrenics almost never yawn, but people with brain lesions, or opium addicts going through withdrawal yawn constantly. Conditions that decrease the quantity of blood directed to the brain, such as haemorrhage and motion sickness, provoke fits of yawning in the sufferers. This leads Baenninger to think that, although yawning is not directly linked with the level of oxygen or carbon dioxide, it has something to do with the blood that carries it. Yawning ensures that the brain has its fill of blood. And a well irrigated brain cannot be a bad thing.

Like everything under the sun, yawning has been used as a therapeutic tool. Dr Cabanès finds it a salutary activity that should be encouraged and recommends it for its healthy action on the Eustachian tubes in larynx troubles.[5] Noëlle Perez-Christiaens, a French yoga teacher, has devoted a whole book to yawning and its use in easing and facilitating the attainment of yoga postures.[6] To my knowledge, the greatest enthusiast must be Janet Goodrich who, in her book Natural Vision Improvement, lists the "many benefits to unbridled yawning".[7] Here are some of these: "…a really good yawn will contract and expand muscles from the top of your head to the tips of your toes… yawning changes the pH of the blood… opens the mind to new experiences… detoxifies the liver… wakes you up in the morning… stimulates the production of refreshing tears… relaxes the solar plexus and tummy muscles…" and so on.

All that does not tell us why yawning should be contagious only in humans. The infectious nature of yawning does not start before we reach two years-old even though babies yawn in the womb. Two years is also the age when infants recognize themselves in a mirror, indicating that they have become conscious of themselves and, therefore, conscious of the lives of others. According to Deputte, the communicability of yawning in humans proves their faculty for empathy and shows "the subconscious desire to harmonize oneself with the physiological state of others". I wonder what would happen if everybody on this planet were to yawn together.

Clearly, there are still a lot of unknown quantities about the simple act of yawning. But if all this has made you yawn, you won't have wasted your time: yawning will have primed your brain for your next task. As it, hopefully, has mine.

References

1 Fischetti A. Je baîlle donc nous sommes. Charlie Hebdo. 16 December 1998.
2 Alexander FM. Man's Supreme Inheritance. Chaterson lTD. London. 1946.
3 Adams A. The Big Yawn. New Scientist. 19/26 December 1998-January 1999.
4 Ibid.
5 Cabanès Dr. Les Fonctions de la Vie. Librairie E. Le François. Paris. 1926.
6 Perez-Christiaens N. Une Thérapeutique naturelle: Le Baîllement. Chiron. Paris. 1980.
7 Goodrich J. Natural Vision Improvement. Celestial Arts. California. 1985.