Hyperventilation is rapid or deep breathing, usually caused by anxiety or panic. This overbreathing, as it is sometimes called, may actually leave you feeling breathless.
When you breathe, you inhale oxygen and exhale carbon dioxide. Excessive breathing may lead to low levels of carbon dioxide in your blood, which causes many of the symptoms that you may feel if you hyperventilate.
Often, panic and hyperventilation become a vicious cycle -- panic leads to rapid breathing while breathing rapidly can make you feel panicked.
If you frequently overbreathe (sometimes referred to as hyperventilation syndrome), this may be triggered by ongoing emotions of stress, anxiety, depression, or anger. However, hyperventilation from panic is generally related to a specific fear or phobia, such as a fear of heights, dying, or closed-in spaces (claustrophobia).
If you have hyperventilation syndrome -- that is, if you regularly hyperventilate -- you might not be aware of it. But you will be aware of having many of the associated symptoms, including dizziness or lightheadedness, shortness of breath, belching, bloating, dry mouth, weakness, confusion, sleep disturbances, numbness and tingling in your arms or around your mouth, muscle spasms in hands and feet, chest pain, and palpitations.
For further information, please see www.nlm.nih.gov/MEDLINEPLUS/ency/article/003071.htm