By Logan WrightYawning is usually seen as indicative of tiredness or boredom, but people have been known to yawn in other situations. Anaerobic athletes such as weightlifters or sprinters sometimes notice themselves yawning during intense workouts or competitions. Yawning, which is not limited to humans, is also inexplicably contagious. If someone near you yawns, there is a good chance you’ll join them soon.
One hypothetical function for yawning relates to an accumulation of carbon dioxide. This makes some sense at first, but upon closer inspection, it fails to explain all yawning. For example, why should it be so damned contagious?
More information: Can you catch a yawn?
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