Why do we Yawn?

Yawning is one of the most natural things. We assume that a person yawns when he is sleepy, tired or bored, this however, is not completely true. Scientists say that a yawn is a respiratory reflex which regulates the carbon dioxide and oxygen levels in the blood. Yawning might be a result of boredom but once we yawn, the sudden intake of oxygen increases the heart rate and you are active and alert once again. So next time you are bored be sure to yawn, (especially in class) and you'll be alert once again.

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