Why Do We Yawn? What Is It's Purpose?

I know it's kind of a crazy question, but i was thinking about it and was wondering why we yawn ... i mean it really feels like it does nothing for me when i do. i was looking into some stuff and found many different explanations....

What's behind this mysterious epidemic of yawning? First, let's look at what a yawn is. Yawning is an involuntary action that causes us to open our mouths wide and breathe in deeply. We know it's involuntary because we do it even before we are born. Research shows that 11-week-old fetuses yawn. There are many parts of the body that are in action when you yawn. First, your mouth opens and jaw drops, allowing as much air to be taken in as possible. When you inhale, the air taken in is filling your lungs. Your abdominal muscles flex and your diaphragm is pushed down. The air you breath in expands the lungs to capacity and then some of the air is blown back out.
Interesting Yawning Facts
* The average yawn lasts about six seconds.
* Your heart rate can rise as much as 30 percent during a yawn.
* 55 percent of people will yawn within five minutes of seeing someone else yawn.
* Blind people yawn more after hearing an audio tape of people yawning. * Reading about yawning will make you yawn.
* Olympic athletes often yawn before competition.

Source

Scientists do not purport to know all of the biological mechanisms of the yawn, but tend to agree that a yawn is an involuntary respiratory reflex, which regulates the carbon dioxide and oxygen levels in the blood. Technically, a yawn is the reflex opening of the mouth followed by the deep inhalation and slow exhalation of oxygen. The very act of yawning is but one of a number of involuntary reflexes controlled by the spinal and nerve centers. Scientists speculate that the onset of a yawn is triggered either by fatigue, or by sheer boredom as, at those times, breathing is shallow, and little oxygen is carried to the lungs by the oxygen-toting cardiovascular system. When one yawns, his or her alertness is heightened, as the sudden intake of oxygen increases the heart rate, rids the lungs and the bloodstream of the carbon dioxide buildup, and forces oxygen through blood vessels in the brain, while restoring normal breathing and ventilating the lungs.

Source

The most plausible explanation, and the one that is taught in medical school, is that we yawn because oxygen levels in our lungs are low. Studies have shown that during normal, at-rest breathing, we don’t use anywhere near our lung capacity; for the most part, we just use the air sacs at the bottom of the lungs. If the air sacs, called alveoli, don’t get fresh air, they partially collapse and the lungs stiffen a bit. As a result, it’s believed, our brain prompts the body to either sigh or take a yawn to get more air into the lungs.

But certain aspects of yawning remain even more mysterious. Fetuses, for instances, have been observed yawning in the womb, yet it’s known that they don’t take oxygen in through their lungs. And yawning seems to be a symptom of multiple sclerosis and other medical conditions, for reasons unclear.

Source

So it seems to me that nobody really knows why we yawn, so i was just posting this here to see what others thought... possibly other theories??

[edit on 9-10-2008 by baseball101]

i though we yawn so we can get rid of some toxins produced by our body but im no scientist... but i yawn QUITE frequenlty like...all the time

I yawned all the way thru the first post. Seriously, good post. But it did make me yawn. I thought it had something to do with not enough oxygen in the blood?

We yawn because we are bored, and we want the speaker, whom we can't walk out on because it would be rude! It is our signal for him/her to freakin' shut up!

The mighty and long YAWN!
I have this wild Idea about yawning..
When one person yawns, and finishes their yawn, another person somewhere in the world yawns.. There is a never ending Yawn going on around this earth!
Many people are yawning at the same time.. But I feel its like a cycle that sweeps across this earth! Much like the WAVE at a big game.
it starts on one end, and works it way around the world, and back again.

If you see someone yawn.. You are more prone to yawn after them.
Hence the Yawning wave affects people just by hearing or seeing a yawn.

What purpose does it serve? Prehaps its a natural reaction of the body to tell the mind we are either bored. Or tired...

I dont know.. But what I do think I know is yawning travles around the world, and with as many people as we have on this earth..
The Yawns never stop!!
Collectively its one long and huge YAWN that never ends, until we all go to sleep.. the big rest.. Death.

It is my opinion that the main purpose of a yawn to to rapidly increase oxygen levels in your body, mainly in your bloodstream. When I was in the Navy I was a corpsman and worked for some time at the NICU (Neonatal Intensive Care Unit). As a low level Corpsman I had the menial jobs like washing, changing and feeding. I also had to do several "assist" jobs for the Drs. during some procedures.

If anyone else here has worked with premature babies they will contest to the fact that the biggest problem with premies is their lung development. Because of this the Drs. usually had to do alot of Blood Gases, in which the test the blood to make sure everything was in balance with oxygen and Carbon Dioxide.

One of my assist jobs was a nurse would come by and sticky an incubator with a note and they would also let me know that the baby was going to get an art gas in about 10 minutes, my job then was to closely observe the baby for any abnormalities in the babies breathing and this included yawning.

I once asked a Dr. why yawning was so important to watch for and he told me that yawning will give a "false" test result and there is little time to correct a problem especially when the patient is so little. He said that if the baby yawned prior to an art gas the results would be better then what is really going on. He said that yawning is a brain response to the blood that it is receiving being out of sorts. That is why yawning happens alot when you are sleepy. He said when you get sleepy your breathing slows way down in preperation for sleep. If you do not fall asleep your brain then starts to recieve less oxygen then it needs in alert mode.

That was the explanation I received and it has always made the most sense to me, I hope it helped.

[edit on 9-10-2008 by jwstarry]

I tend to yawn when my peers talk to me about politics, really boring listening to people who don't know what there talking about, also I believe yawning provides stress relief

Yawn

I yawn constantly. I'm really bad for it.

I do belive that yawning can sometimes be to increase oxygen in your bloodflow, but I don't think that's the only answer. How would that explain me yawning practically non-stop for hours every day? I'm breathing the same air as everyone else. It also doesn't explain why we yawn when we're bored.

I think there's a social function or some other envirenmental trigger associated with yawning.

Personally, i love it. It makes me feel good.

I stumbled across this guy recently www.yawnguy.com.... Now I can explain to my partner that i'm not bored and i'm not tired, i'm just letting out some negative energy, that's all

I work in EMS, and once asked a Nuerologist about this. He said it was akin to the brain "stretching"

I remember once learning that yawning is a hold over from evolution. If my memory holds, it was stated that animals yawn, ironically, to wake themselves up. This explains why yawns are contagious. When an animal in a group yawns, thus forcing the other animals in the group to yawn, it helps to ensure that someone is staying awake, and thus, keeping watch over the pride, herd, or flock. However, I am pretty sure that it was at least a decade ago that I learned this and given that science is continually changing, this opinion may be out of date. Actually, in typing this post I think it may have been that yawning was a way for members in a group of animals to give an indication to other members of the group that they may fall asleep soon and that they would no longer be keeping watch, thus ensuring that someone would take over their duties. But again, this theory may be out of date.

hmmm very interesting theories ... thanks jwstarry for posting that it seems pretty legitimate to me, but i'm not sure i was doing some research and there are others out there who have the same beliefs ... there was one site i went to that said that when you yawned it was your brain giving itself a "hit" of oxygen and here's another study saying that yawning somehow cools the brain...

The psychologists, who studied yawning in college students, concluded that people do not yawn because they need oxygen, since experiments show that raising or lowering oxygen and carbon dioxide in the blood fails to produce the reaction. Rather, yawning acts as a brain-cooling mechanism. The brain burns up to a third of the calories we consume, and as a consequence generates heat.

According to Gallup and Gallup, our brains, not unlike computers, operate more efficiently when cool, and yawning enhances the brain’s functioning by increasing blood flow and drawing in cooler air.

Source
I'm really open for anything ... there are soo many different theories out there, but none that have a definitive answer

[edit on 9-10-2008 by baseball101]

I heard somewhere that we yawn to equalise pressure in the ear drums or something

Hi, my first time posting on ATS to answer this question.

It was actually discovered rather recently that yawning is designed to transfer heat flow from the brain out into the environment. Over time, the brain does a lot of thinking and overheats; by evening (when most people yawn) it needs to channel the heat elsewhere, and that is through our breath. They discovered this by observing monkeys, IIRC.

Hope that makes sense. Have you ever tried yawning "quickly"? Your breath is always warm.

I thought it was to release toxins and buffer neurotransmitters. Have read that a lot of schizophrenics don't yawn much, so that would sort of make sense.

My dog yawns when I yawn...

Spying someone yawning often makes us yawn. Now, a new study shows your canine buddy can catch yawns from you, too. The results suggest domestic dogs have the capacity for a fundamental form of empathy, the researchers say....

Dogs Can 'Catch' Yawns From Humans, Study Finds

well yawning is a very deep breath the usual cause of it is that we are tired and our breathing has fallen below what is needed so we are trying to make. It up quickly!?!
Added by BIBI !!??

Originally posted by BluegrassRevolutionary
I remember once learning that yawning is a hold over from evolution. If my memory holds, it was stated that animals yawn, ironically, to wake themselves up. This explains why yawns are contagious. When an animal in a group yawns, thus forcing the other animals in the group to yawn, it helps to ensure that someone is staying awake, and thus, keeping watch over the pride, herd, or flock. However, I am pretty sure that it was at least a decade ago that I learned this and given that science is continually changing, this opinion may be out of date. Actually, in typing this post I think it may have been that yawning was a way for members in a group of animals to give an indication to other members of the group that they may fall asleep soon and that they would no longer be keeping watch, thus ensuring that someone would take over their duties. But again, this theory may be out of date.

Yeah, I read the same thing. When groups of humans were out in the wilderness, some had to be alert so yawning either woke them or alerted others that they were about to fall asleep. But it is contagious so that the small group of people who were guarding the fire or against other groups or animals, would all be more awake.

I have come up with another reason too. Some people find that when they yawn, they involuntarialy have a jet of saliva shoot out of their mouths. I can do this by will, by pushing out the bottom of my tongue. However, once the saliva in the glands has been used up, the only way I can get more in there is to yawn. Then the glands fill up with saliva once more.

So I think that yawning has many aspects to it, perhaps one also is to make sure there is enough saliva in the glands so your mouth doesn't dry up whilst alseep.

Also have you noticed that when you yawn, it starts at the back of your mouth, not in your diaphragm like you'd expect if it was to bring in a sudden influx of oxygen.

Just another idea!

reply to post by baseball101


We yawn to equalise pressure between the outer and inner ear, via the eustacian Tubes. Loss of pressure is more apparent when tired.

Originally posted by KRISKALI777
reply to post by baseball101

 

We yawn to equalise pressure between the outer and inner ear, via the eustacian Tubes. Loss of pressure is more apparent when tired.

I get a yawning fit when I have an allergic reaction, soon after the symptoms of streaming eyes and catarrh appear. So your explanation makes sense in my case.

There is also a neurological connection between sexual arousal and yawning in males. The same chemical messenger mediates both (I think it's nitrous oxide if I recall correctly). So one can trigger the other.