Why is hyperventillation dangerous?

I've used hyperventillation many times before, but nothing happens to me. Then I hear it is dangerous. I wonder why.
Answer:
Your body must have a certain level of carbon monoxide to stimulate the respiratory center in the brain in order maintain a respiratory function.That's controlled by the "autonomic" nervous system.When you hyperventilate you blow all your CO2 out and the the O2 blood levels go way up,and it acts like a toxin and decreases the ability to have a normal breathing cycle,and you gasp and pant very shallow breaths.In order to stop that cycle,you must breathe into a paper bag for several minutes,breathing in the CO2 needed to get the brain's respiratory center back in its natural rhythm.Take care SW RNP

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if you are referring to the use if it in diving, it is because of the possible disorienting effect of elevated oxygen levels. You realize that people pass out from hyperventilation right? There is a reason for that. It is the body's defense mechanism used to restore breathing to normal levels. Passing out when diving is usually a bad thing.

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Sharon got it pretty much right, other than it's carbon dioxide (one carbon molecule, two oxygen molecules) not monoxide:-)I can also point out that when swimmers hyperventilate it is to lower the carbon dioxide levels in the blood. When you hold your breath, it isn't the lack of oxygen telling you that you need to breathe again, it is the INCREASING carbon dioxide levels in the blood. Hence, hyperventilation increases the time between holding your breath and your brain's respiratory centre telling you to take another breath.

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you cant get enough oxygen to your body to allow gas exchange to occur. i hyperventilate when i cry and if it lasts long enough i begin to feel dizzy.

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