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Why Do We Yawn?

A “yawn” as defined by is said to be “to open the mouth somewhat involuntarily with a prolonged, deep inhalation and sighing or heavy exhalation, as from drowsiness or boredom.” The word yawn is derived from the Old English word meaning to gape or open wide. The average human yawns 240,000 times in a lifetime and the average yawn lasts about six seconds. 1

Many believe that a yawn is in response to excess carbon dioxide or shortage of oxygen in the lungs. This notion is false and probably assumed because of the gasp that takes place at the end of yawns.

While yawns are typically seen as a comical occurrence, it is now known that excessive yawning can signify a brain tumor, hemorrhages, opiate withdrawal, chorea, encephalitis and other internal issues. 2

Stretching is usually accompanied by a yawn; however, they are not dependent on each other. Also, the face that is formed when yawning stretches the face and is possibly one of the reasons that yawns are so satisfying. On a scale from one to 10 (10 being most satisfying), the average rating was 8.5. 2

All vertebrate animals yawn in the same fashion as humans. Also, yawning is not exclusive to mammals. Crocodiles, sharks, snakes and birds all yawn. 1 The purpose of their yawning is unknown as well.

Reading about yawning stimulates yawns, similarly to seeing someone yawn makes you have to desire to yawn. (I’ve yawned about 30 times while writing this). The yawn alone is not what is contagious. In fact, the entire facial stretch that accompanies the yawn causes others to feel the need to replicate the face. Therefore, even when you cover your mouth, the “yawn face” is still present in the eyes and can cause others to yawn. Contagious yawning is thought to be an ancient way of communicating bedtime. 2

Recent studies have shown that yawning may not be linked to sleepiness or boredom whatsoever, and may be needed in order to cool the brain. 3 This theory is generated from medical observations such as epileptics yawning excessively before a seizure. Now yawning can be used as a signal to greater problems, especially with diseases or disorders that affect the brain’s temperature. Additionally, some animals that do not sweat such as dogs and pigs may use yawning to cool their bodies, even if just by a fraction of a degree. 2

While most aspects of yawning are still a mystery, it is clear that if you are yawning very often you are likely not getting enough sleep or extremely bored. Though many theories are continuously being developed, no proven function has been identified.


1. WebMD—What’s in a Yawn?

2. Maas, Dr. James B., Megan L. Wherry, David J Axelrod, Barbara R. Hogan, and Jennifer A. Blumin. Power Sleep: The Revolutionary Program That Prepares Your Mind for Peak Performance. New York : Villard, 1998.

3. USA Today—Yawning may cool brain when needed;

17 Comments Post a comment
  1. Very interesting article

    September 14, 2012
  2. Very interesting! Never knew a yawn was so complicated!!!

    September 14, 2012
  3. You learn something new everyday!

    September 14, 2012
    • Bradley Simons #

      We try our best to learn something new everyday. Today’s Lesson is; you are our free ChiroMax Pillow winner. Thank you for your participation.

      September 17, 2012
  4. I must have a very warm brain…*yawn 😉

    September 14, 2012
  5. Just reading this made me want to yawn…Yawning is contagious…okay I gave in and yawned…not good this early in the morning :0 )

    September 14, 2012
  6. I have often wondered about the yawn especially in reference to how it is considered contagious. Thanks for the info! I must be sleep deprived with a new baby and waiting on my bed in a box purchase to arrive

    September 14, 2012
  7. Thanks for the information on facial stretching as I am a massage therapist and this is good info to know. Hopefully when I get my bed in a box I will yawn less because I will be sleeping like a baby when I’m not up with the baby! Thanks again Bethany Nelson!

    September 14, 2012
  8. i yawned when i read the artical.. lol made me do it. yawning is contagious, i see people yawn in the car next to me and right away i do it!

    September 14, 2012
  9. Very interesting article; I wasn’t aware of the theory that yawning might cool the brain’s temperature. Thank you!

    September 14, 2012
  10. I always thought that yawning was from a lack of oxygen to the brain.

    September 14, 2012
  11. Someone needs to do a sleep study on me to find out why I’m constantly exhausted but still can’t get an uninterrupted night’s sleep. Blah.

    September 14, 2012
  12. You know what would help me with my yawning? A new pillow.

    September 14, 2012
  13. Never thought about yawning while reading about yawning but it happened to me. Good luck with the Sleep Academy and congratulations on your first authorized dealer. I predict Bed In A Box stores nationwide.

    September 14, 2012
  14. Interesting. Definately noticed that when one person yawns, others usually do too.

    September 14, 2012
  15. No wonder i quit yawning . I have a new bed in the box mattress

    September 14, 2012
  16. so strange that the cause isn’t known

    September 15, 2012
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