ELI5 : Why do we yawn, when we are tired or sleepy?

r/

ELI5 : Why do we yawn, when we are tired or sleepy?

Comments

  1. star_blazar Avatar

    I want to know, too! With the neurological disease I have, yawning is also a precursor to having a functional seizure at times. I was hoping to see how that relates

  2. wille179 Avatar

    Yawning is thought to be a reflex your brain triggers to briefly force you to breathe more and spike your heart rate to wake you up. It also works as an instinctive social cue, basically “Hey I’m tired, you might be too,” which is why it’s contagious.

    Scientists aren’t 100% sure though. This is just one of our best theories.

  3. loveandsubmit Avatar

    There seem to be a lot of reasons for yawning. One theory that I think has merit is that, as you start to feel tired, your body begins to relax and prepare for sleep automatically. This includes slower, more relaxed autonomous breathing. If you’re fighting to stay awake, your body/brain may need a little more oxygen than your slower breathing is providing, and yawning is a mechanism to increase oxygen supply.

    But, afaik, there hasn’t been any conclusive study to determine how true that might be.

  4. Jedisacat Avatar

    Another theory is that yawning can be a warning system.

    If there is something on the air putting you to sleep, yawning makes you aware and acts as a social signal to others in the same space that there may be a poor air quality and leave.

    E.g. carbon monoxide poisoning