What causes yawns?

Answer 1

causing yawning can be because you are tired or did not get enough sleep

There are a number of theories that attempt to explain why animals and people yawn. It is likely that there are a number of triggers for the behavior. However, there are a few theories that attempt to explain the primary evolutionary reason for the yawn. None of them has been empirically substantiated.

One study states that yawning occurs when one's blood contains increased amounts of carbon dioxide and therefore becomes in need of the influx of oxygen (or expulsion of carbon dioxide) that a yawn can provide.Yawning may in fact reduce oxygen intake compared to normal respiration However, neither providing more oxygen nor reducing carbon dioxide in air decreased yawning

Another speculated reason for yawning is the desire to stretch one's muscles. The tongue and throat are some of the most used muscles in the body, used for speech, breathing and swallowing. The need to stretch these muscles and refresh them arises just like in other muscles of the body, to circulate lymph. Yawns are often accompanied by the urge to stretch. Still another proposal points out that animals subject to predation or other dangers must be ready to physically exert themselves at any given moment. At least one study suggests that yawning, especially psychological "contagious" yawning, may have developed as a way of keeping a group of animals alert

Answer 2

a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath. Pandiculation is the term for the act of stretching and yawning simultaneously.Yawning is also associated with tiredness, stress, overwork, lack of stimulation, or boredom. Yawning can also be a powerful non-verbal message with several possible meanings, depending on the circumstances. In humans, yawning has an infectious quality, i.e. seeing a person yawning, or just thinking of yawning, can trigger yawning which is a typical example of positive feedback.Some claim that yawning is not caused by lack of oxygen, for the reason that yawning allegedly reduces oxygen intake compared to normal respiration. Another speculated reason for yawning is nervousness and is also claimed to help increase the state of alertness of a person - paratroopers have been noted to yawn in the moments before they exit the aircraft.__ Angara Exantus

Answer 3

Yawning is associated with tiredness, stress, overwork, lack of stimulation, or boredom. Yawning can also be a powerful non-verbal message with several possible meanings, depending on the circumstances. In humans, yawning has an infectious quality (i.e., seeing a person yawning or just thinking of yawning, can trigger yawning) which is a typical example of positive feedback. Infectious yawning has also been noted in chimpanzees.a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath. Pandiculation is the term for the act of stretching and yawning simultaneously.Yawning is also associated with tiredness, stress, overwork, lack of stimulation, or boredom. Yawning can also be a powerful non-verbal message with several possible meanings, depending on the circumstances. In humans, yawning has an infectious quality, i.e. seeing a person yawning, or just thinking of yawning, can trigger yawning which is a typical example of positive feedback.Some claim that yawning is not caused by lack of oxygen, for the reason that yawning allegedly reduces oxygen intake compared to normal respiration. Another speculated reason for yawning is nervousness and is also claimed to help increase the state of alertness of a person - paratroopers have been noted to yawn in the moments before they exit the aircraft.