They say that yawning is a way to deliver more oxygen to the brain. But what is it about being tired that requires us to yawn? Doesn’t our brain always need oxygen? Does a tired body become less effective at delivering and using oxygn? Or does a tired mind need to use more? Do elements of the respiratory system slow down down when we are exhausted? Do the lungs have to work harder? Is less of our oxygen intake able to be process?
does anyone else think about yawns? (I can probably answer that one!)
PS. Wikipedia totally kills urban legends. )=