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Animals do it, too. But why, exactly, do people and animals yawn? No one knows for sure. But there are many theories ideas about why people yawn. One is that when we are bored or tired, we just don't breathe as deeply as we usually do. A number of theories regarding the genesis of yawning have been presented over the years. Some evidence suggests that yawning is a means of communicating changing environmental or internal body conditions to others. If so, then its contagious nature is most likely a means of communication within groups of animals, possibly as a means to synchronize behavior.

If this is the case, yawning in humans is most likely vestigial and an evolutionarily ancient mechanism that has lost its significance. Yawning is a stereotypical reflex characterized by a single deep inhalation with the mouth open and stretching of muscles of the jaw and trunk.

It occurs in many animals, including humans, and involves interactions between the unconscious brain and the body, though the mechanism remains unclear.

As for the etiology of yawning, for many years it was thought that yawns served to bring in more air because low oxygen levels were sensed in the lungs. We now know, however, that the lungs do not necessarily sense oxygen levels. Moreover, fetuses yawn in utero even though their lungs arent yet ventilated. In addition, different regions of the brain control yawning and breathing. Still, low oxygen levels in the paraventricular nucleus PVN of the hypothalamus of the brain can induce yawning.

The results showed that the less empathy a person had, the less likely they would yawn after seeing someone else yawn. If you feel yourself yawning excessively, try deep breathing exercises through your nose. Your body may need more oxygen. A study also found that nasal breathing decreased contagious yawning completely in their research.

Breaking up a routine can also help stimulate your brain. Feelings of tiredness, boredom, and stress tend to make people yawn more. Excessive yawning may also stem from taking in too much caffeine or going through an opiate detox.

You can also try taking a walk outside or finding a space with a cooler temperature. Tell your doctor when the yawning started and about other symptoms, such as mind fog, pain in certain areas, or even lack of sleep.

This information can help your doctor diagnose the underlying condition and make treatment recommendations based on individual needs. There are many theories behind why we yawn. Read our tips on sleep hygiene for better quality sleep. Yawning is a natural response to being tired. Excessive yawning is yawning that occurs more than once per minute.

The link between empathy and contagious yawning is further supported by the data collected by Campbell and de Waal. The ingroup videos were shown before the outgroup videos to all the subjects. It was ensured that all the subjects paid similar attention to both types of videos. Each chimpanzee was exposed to the videos for a total of 20 min on one or more days, depending upon his interest and cooperativeness, to eliminate the effect of stress. Also, none of the test subjects were able to see the other chimpanzees while viewing the videos.

Even though, the authors do maintain that their results suggest a possible relationship between yawning and empathy, yet they also admit a few limitations of their study. This may be due to the fact these animals are territorial and form small coteries, which are aggressive to neighboring ones. Such a kind of behavior is absent in humans since the latter do not always view strangers as belonging to an outgroup.

It is thus concluded that yawning may be a part of action repertoire of empathic and communicative processes in adult humans and some other mammals which provide for a strong social role of yawns in these species. Yawning relieves the ear discomfort and hearing problems that are commonly experienced by people during rapid altitude changes in airplanes and elevators.

This is achieved by opening of the eustachian tubes due to the contraction and relaxation of tensor tympani and stapedius muscles. An crucial experimental evidence that provides support to the above proposition comes from the work of Winther et al. The contrast material was detected in middle-ear by computerized tomographic scan of the temporal bone. However, since the eustachian tube can also be opened by swallowing and Valsalva manoeuvre, thus yawning, by itself, does not appear to offer an indispensable evolutionary advantage of releasing middle ear pressure.

The latter effect thus does not seem to be the primary purpose of yawning. For the past several centuries, a commonly held notion associated with yawning is that it is triggered when blood or brain oxygenation is insufficient, that is, when oxygen O 2 levels decrease and carbon dioxide CO 2 concentration rises. However, this belief has been discarded in wake of the results of a recent study in which the yawning frequency was unaffected in subjects who breathed air mixtures containing either more than normal CO 2 or even pure O 2.

Yawning research is intriguing because the ubiquity of this phenomenon across most of the vertebrate classes and even in a 20 week old human fetus,[ 9 ] suggest that considering it merely as an act of boredom and drowsiness is unjustified and that it may have a definitive underlying physiological importance which needs to be meticulously explored. However, till we get a conclusive answer, it is safe to assume that yawning could represent a para-linguistic signal that may have multiple functional outcomes across various species.

The authors would like to thank Robert R. Provine and Oliver Walusinski for their invaluable online archive of articles on yawning, which greatly facilitated the research for literature for this article.

Source of Support: Nil. Conflict of Interest: None declared. National Center for Biotechnology Information , U. Sharat Gupta and Shallu Mittal 1. Author information Article notes Copyright and License information Disclaimer.

Address for correspondence: Dr. E-mail: ni. Received Aug 20; Accepted Mar This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.

This article has been cited by other articles in PMC. Abstract Although yawning is a commonly witnessed human behavior, yet it has not been taught in much detail in medical schools because, until the date, no particular physiological significance has been associated with it. Keywords: Arousal, brain thermoregulation, empathy, yawning.

Footnotes Source of Support: Nil. Askenasy JJ. Is yawning an arousal defense reflex? J Psychol. Provine RR. Yawning as a stereotyped action pattern and releasing stimulus.

Am Sci. Simonds AK. Curbside consult: Why do people yawn? West J Med. Walusinski O. Popular knowledge and beliefs.