March 4, 2007 8:43pm CST
why does a person suddenly stretch his mouth wide open, take a deep breath,and give forth a sigh? or yawn? what does it signify??
27 Mar 07
Yawning is an involuntary response that have baffled humans for decades and even though we may have more knowledge through the advancement in science and technology, the mystery of why we yawn is still not completely solved yet. It is still not known exactly how a yawn occurs. The brain being the most sophisticated organ in our possession might be the key to this discovery. After all, the human brain has about 100 billion neurons which connect to thousands of other brain cells. Each playing their job in different regions of the brain through a huge network system. Did you yawn while reading all of this? If you did, I hope it was not from boredom. I am yawning as this sentence is being written (YAWN).
9 Apr 07
There seem to be three main theories as to why people do it. I think it comes down to reducing the percentage of carbon dioxide we have in our blood streams, and fatigue. I also do it automatically if my ears need to be popped. At Howstuffworks.com, here are the three big theories: "The Physiological Theory -- Our bodies induce yawning to drawn in more oxygen or remove a build-up of carbon dioxide. This theory helps explain why we yawn in groups. Larger groups produce more carbon dioxide, which means our bodies would act to draw in more oxygen and get rid of the excess carbon dioxide. However, if our bodies make us yawn to drawn in needed oxygen, wouldn't we yawn during exercise? Robert Provine, a psychologist at the University of Maryland, Baltimore County, and a leading expert on yawning, has tested this theory. Giving people additional oxygen didn't decrease yawning and decreasing the amount of carbon dioxide in a subject's environment also didn't prevent yawning. The Evolution Theory -- Some think that yawning is something that began with our ancestors, who used yawning to show their teeth and intimidate others. An offshoot of this theory is the idea that yawning developed from early man as a signal for us to change activities. The Boredom Theory -- In the dictionary, yawning is said to be caused by boredom, fatigue or drowsiness. Although we do tend to yawn when bored or tired, this theory doesn't explain why Olympic athletes yawn right before they compete in their event. It's doubtful that they are bored with the world watching them."
28 Mar 07
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.
• United States
27 Mar 07
No one knows why people yawn, its thought to be from boredome or being tired. Old thoughts were that its to oxygenate the blood, but that's false. I just finished a physiologic psychology class studying brain function...and this was one of the study topics. People who yawn when seeing another yawn show empathy. People without empathy or consciousness of self, don't.
18 Mar 07
A yawn is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from lack of stimulation. Yawning is a non-verbal message with several possible meanings:an indication of tiredness, stress, over-work, or boredom. It is an action indicating psychological decompression after a state of high alert and as means of expressing powerful emotions like anger, apathy, remorse or tedium. A previous long-standing hypothesis is that yawning is caused by an excess of carbon dioxide and lack of oxygen in the blood. The brain stem detects this and triggers the yawn reflex. The mouth stretches wide and the lungs inhale deeply, bringing oxygen into the lungs and hence to the bloodstream.
12 Mar 07
I do know that when a room builds up in carbon dioxide, a lot of people in the room, the carbon dioxide causes you to become sleepy and you begin to yawn even if you are not tired. It would seem to me that yawning is the streching of the neck and head muscles in order for the veins to constrict and move blood more rapidly to the brain. So hypoxia of the brain or carbon dioxide would trigger it.
5 Mar 07
I agree with Caribe. However I'd add that when we're overly relaxed we have an excess of oxygen, which we release by yawning. We take deep breaths because having a lot of oxygen keeps the body relaxed, (that's why when we're tired we breathe faster, we need more oxygen to be more relaxed). And when we're overly relaxed, we release that extra oxygen. The baby thing, I'd say it is genetics, but I'm a physicist, not a physician
• United States
5 Mar 07
There are a lot of theories about yawning but I don't think anyone is positive. One theory is that the body lacks oxygen and that most people when resting don't use most of their lung capacity. On the other hand, babies still in the womb have been see yawning and they are not using their lungs yet. Maybe we are tired or just bored. Most animals yawn, as well. Yawning is very suggestable. I am yawning just sitting here writing about it.