When you yawn, Why do your eyes water?
450975
the act of yawning squeezes the tear glands
414151
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. \n\nThere 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. \n\nWhile the dictionary tells us that yawning is caused by being fatigued, drowsy or bored, scientists are discovering that there is more to yawning than what most people think. Not much is known about why we yawn or if it serves any useful function, and very little research has been done on the subject. However, there are several theories about why we yawn. Here are the three most common theories: \n\n\nThe 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. \nThe 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. \nThe 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. \nThe simple truth is that even though humans have been yawning for possibly as long as they have existed, we have no clue as to why we do it. Maybe it serves some healthful purpose. It does cause us to draw in more air and our hearts to race faster than normal, but so does exercise. There's still much we don't understand about our own brains, so maybe yawning is triggered by some area of the brain we have yet to discover. We do know that yawning is not limited to man. Cats, dogs, even fish yawn, which leads us back to the idea that yawning is some form of communication. \n\nHave we provoked a yawn out of you yet? If we have, hopefully it's not out of boredom, but by the power of suggestion.
292667
Because when you open your mouth and the ear comes in as negative pressure; the ostacious tube which is a canal connecting middle ear to the pharynx is increase in pressure by air; then pushes the ear drum to out side (slightly) so the sensitivity to sound waves decreases, that is why sometimes we cant hear the sounds while we are yawning.
71555
Your eyes run water when you laugh for the same reason they run water when you cry. Certain emotional responses activate the parasympathetic division of the autonomic nervous system. When the parasympathetic system is stimulated, it causes the tear glands to secrete fluid. Therefore, your eyes run water. Like most things, it varies from person to person and some people have more response than others. Don't worry about it. Enjoy the laughter.
757509
sometimes if your eyes are really dry, it stings when your eyes water,  you should put eye drops in them to water them up
1016916
when they, do is maybe because they yawn and eyes get watery. When you feel  sleepy your eyes feel heavy and sometimes itch. Why not rub them?
337591
because yawns are catching and a yawn is when you are tired and need a hugeee gulp of air so of course if someone in your group has yawned and inhaled alll the air then you nearly suffocate cause you've got no air so you have to yawn to try get some air before you collapse. so blame you friends for snatching the air from your lungs making you yawn !!!!!!!!!!!!!!!!!!!!
748622
It could be that that particular eye is dry, sometimes when our eyes or one eye is dry the body compensates by sending more water to the dry part of the body thus causing it to water.  Try seeing your doctor to make sure nothing out of the ordinary is going on inside of you.\n\n\nHope this helps
726200
People who have poor sleeping habits usually experience this. A high sodium diet or drinking water near bedtime can cause fluids to be retained in the eye. Normally, this should not happen. But poor sleep causes the body to forego some functions, like deal with water in your eyes.\n\nThat is why most beauty gurus recommend a cold compress to get down the swelling (it is similar to swelling in some injuries). Also, since it goes away as the day passes, that means that it is nothing serious, and is most likely related to a habit, like sleep :)
345570
Yawn while opening your mouth wide open. Wide as possible.
198710
When you yawn, you are attempting to take in as much air as possible, more oxygen gives more energy.  People in the immediate area are in competition for this air too and yawn as a response to retrieve air themselves
1159613
Ahhh... the age old question. lol\n\nThere are a number of theories. One is that when someone yawns, they take oxygen out of the air, and we need the oxygen so we yawn to get the oxygen we need. I'm not sure about that one. I think its just a joke.\n\nA more likely theory is that it relates back to the herd instinct. You know, monkey see, monkey do.
153961
Do your eyes only get watery when you wake up?  You could be responding to dry air or it's possible that you have an allergy.  You may want to see your eye doctor to see what he/she recommends.  If it's an allergy, you may need some special eyedrops to help alleviate the symptoms.
33139
we yawn to equalise the pressure difference between our ears and the outside. when u yawn you equalise the pressure in your ears but there is a disbalance created in the atmosphere and hence others around you also start yawning....!!!!
305821
You yawn because there's not enough oxygen in the air and your body just does that to get more oxygen in one breath. So tecnicly everybody's not getting enough oxygen.
335882
It is a "associative" reaction. You see someone yawn and it triggers the same reaction because in our experience yawning represents being tired. We therefore associate yawning by others or ourself with being tired.\n\nI get a similar associative reaction when my daughters and I say the Lord's Prayer every night at bedtime. Halfway thru the prayer they will both yawn like clockwork. They both associate the prayer with being sleepy. Puts them right to sleep every time!
300748
WHen you see another person yawning, the message goes across your brain that may be you too needs more oxygen and in attempt to get more air in, you open your mouth wide open, your lungs expand and you yawn. That's why it's called reflex yawning