Pondering the Mystery of Yawning

The video at the bottom of the post is a remarkable 3-D video of a baby yawning in the womb. I was struck at how, while watching it, I began to yawn as well.

I want to say, that yawning is a very deep mystery. I have never heard an explanation for yawning that sounded very convincing. Frankly, honest medical people will shrug and say, no one really knows why we yawn, or why the practice is so catchy. It does seem related to fatigue but not every who is tired yawns.

“Explanations” abound. Hippocrates thought that yawning was to rid the lungs “bad air,” and bring in fresh air. Other have thought it helped get more blood to the brain. Still others hold that yawning helps increase blood oxygen levels and decrease carbon dioxide. But tests don’t really confirm these sorts of things. Put a person in a room with high CO2 and they don’t start yawning. And that surely doesn’t explain why babies who breathe water would yawn in the womb.

Some think yawning helps keep us awake, others think it helps relax us. Some say it helps regulate body temperature. But again tests such using EEGs to monitor brain activity, or taking temperature just don’t confirm this.

Still others think the behavior is related to imitation, empathy and social bonding behavior. But if that is so why do babies alone in the womb yawn? And why do most vertebrate animals, many of which exhibit little social bonding. yawn?

So you see, one of the most common human behaviors is deeply mysterious. We just don’t know why we yawn, or why the behavior is contagious. It is one of life’s imponderables.

One day we will have to ask God. Another mystery to ponder, do Jesus and Mary in their glorified bodies in heaven yawn? Yes, one day all will be reveled. For now, live the mystery and humbly accept a very humbling truth: no one knows why we yawn.

I tell you, I’ve been yawning all through typing this!

17 Replies to “Pondering the Mystery of Yawning”

  1. The yawn is definitely a physiologic response to a neurologic impulse brought on by a psychosomatic reaction to a sensoral aberration. I can’t take credit for it, it’s a gift. Talents on loan from God.

  2. Here is why we yawn:

    We yawn as a way of showing our teeth to the creatures of the night before going to sleep.

    It is a way of saying:

    “Ok, all you critters out there lurking in the dark, I`m off to bed now. But if anyone of you consider trying to eat me while I sleep, be assured that you will meet up with some pretty heavy resistance: Namely my teeth. Take a look – and change your minds. Good night.”


  3. If only parents who are considering abortion could see this video of their child. I don’t believe they would be able to go through with it.

  4. Great piece Msgr. Light-hearted with a profound spiritual insight. Or should I say yawn-hearted?

  5. I’m in medical school and one of the reason that was hypothesized is that yawning acts to counter alveolar collapse (aka atelectasis). We yawn so as to increase alveolar pressure for increasing the radius of the alveoli. The alveoli is basically where gas exchanges take place between the environment and the body so as to provide oxygen to the body. The bigger the alveoli, the more gas exchanges take place. Hence, that is why it is believe we yawn at night is to increase alveoli surface area so that we might have adequate gas exchange during sleep. And when we wake up, yawning helps to open the alveoli again so as to help us with our daily work.

    1. Yes. Most people “sigh” naturally and unknowingly about 6-8 times an hour. Sighs and yawns are protective to the lungs by expanding the alveoli and helping to clear secretions and thereby prevent problems. For example, when patients are placed on mechanical ventilators in ICU’s, if the same tidal volume of air is pumped repeated without variance, then problems such as pneumonias are much more likely to develop. Artificial ventilators have a setting which allows deliverance of higher tidal volumes periodically each hour to mimic the body’s natural sighing.
      In the womb, most likely yawning helps in some manner to mature the lungs and also to help the little person understand how to initiate breathing at birth. Praise Jesus, for He thinks of everything! Human development in the womb is a marvel. Thank You, dear Lord.

      1. I do not think that is an convincing explanation since the lungs have not expended in utero and gas is exchanged through the placenta via a shunt in the heart which means that the pressure in the alveolar would be unlikely changed,

        As for neuromuscular development for babies in the womb, I do not know, but we can know if that is the case by looking at their diagram activity. I do not have access to such info, but if anyone could find out please let me know,

    2. So how is it contagious so you feel the urge to yawn when you see someone else yawn? Definitely a psychosomatic aberration. I don’t think we yawn in our sleep when we are most susceptible to alveolar collapse. I believe that is what causes us to sigh not yawn and that is not contageous. I was a respiratory therapist for about six year back in the 1970’s but not a doctor. A child in the womb is not concerned with alveolar collapse and yet they yawn.

    1. Your welcome Debbie.

      It is true, though.
      Yawning is a way of displaying our defense-capabilities to the world before sleeping. We display our teeth and bite-range as a deterrent to would-be attackers.

      Sleep tight.


  6. People sometimes yawn from anxiety. If a confessional line is especially long, I find myself yawning every 30 seconds or so.

  7. Yawning is the notice that our battery is at <20 percent and should be attached to alternative power. Praying for all of us as always 🙂

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