Yawning

Yawning is a reflex consisting of the simultaneous inhalation of air and the stretching of the eardrums, followed by an exhalation of breath. Yawning (oscitation) most often occurs in adults immediately before and after sleep, during tedious activities and as a result of its contagious quality. It usually lasts six seconds.

Causes[edit | edit source]

The exact causes of yawning are still unknown. However, there are a number of theories that attempt to explain why yawns occur.

Contagious yawning[edit | edit source]

Contagious yawning is triggered involuntarily when you observe another person yawn. It is a common form of echophenomena – the automatic imitation of another's words (echolalia) or actions (echopraxia).

Thermoregulatory theory[edit | edit source]

The thermoregulatory theory of yawning suggests that yawning is a way to cool down the brain.

Evolutionary theory[edit | edit source]

The evolutionary theory of yawning suggests that yawning evolved to help our ancestors stay alert and avoid danger.

Effects[edit | edit source]

Yawning has a number of effects on the body, including increasing heart rate, blood pressure, and blood oxygen levels.

In animals[edit | edit source]

Yawning is not limited to humans. It is also observed in a wide range of animals including mammals, birds and reptiles.

References[edit | edit source]

External links[edit | edit source]

Yawning Resources
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