Humans, on average, yawn about 5 to 20 times every day, and each yawn lasts about 5 seconds
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Yawning is associated with sleep, but it does not indicate a need for sleep, according to scientists
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Also, yawning does not mean one has less oxygen in their body or excessive carbon dioxide, as believed by many
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Yawning is said to be a form of non-verbal communication. Baboons use this as signal to troops that it’s time to sleep
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People yawn when their breathing is shallow, or when they are tired, bored or have just woken up
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Yawning stretches out the lungs and nearby tissues, and prevents tiny airways in the lungs from collapsing
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Yawning helps increase heart rate, stretches muscles & joints, prepares the body for increased alertness, according to Harvard Medical School
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Yawning is an involuntary process that helps cool down the brain, Penn State University article quotes Andrew C Gallup, a researcher in evolutionary psychology
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Humans & chimpanzees show contagious yawning, which refers to the urge to yawn on seeing others yawn
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Yawning could also be a symptom of a disease such as multiple sclerosis or amyotrophic lateral sclerosis, according to Harvard Medical School
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A person may also yawn before they are about to experience a migraine headache
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Yawning could also be a means to help one's mind & body transition from one state to another, and not related to how tired they are