Hyperventilation syndrome may occur when a person breathes from the chest, which can lead to overbreathing (exhaling excessive carbon dioxide in relation to the amount of oxygen in one's bloodstream). Hyperventilation syndrome can cause respiratory alkalosis and hypocapnia. This syndrome often involves prominent mouth breathing as well. This causes a cluster of symptoms, including rapid heart beat, dizziness, and lightheadedness, which can trigger panic attacks.
What happens, exactly? "We all physically respond to stress," says Barbara O. Rothbaum, PhD, psychiatry professor and director, Trauma and Anxiety Recovery Program, at Atlanta's Emory University School of Medicine. "You might feel anxious about work-related problems, taking a big exam, or making an important decision. But someone who suffers from panic disorder may react to those same moderate pressures with an exaggerated physical reaction-as if he or she were about to be attacked by a wild tiger or fall from a great height. It's full-on, adrenaline-pumping, fight-or-flight response."
Occasional anxiety is an expected part of life. You might feel anxious when faced with a problem at work, before taking a test, or before making an important decision. But anxiety disorders involve more than temporary worry or fear. For a person with an anxiety disorder, the anxiety does not go away and can get worse over time. The symptoms can interfere with daily activities such as job performance, school work, and relationships.