The answer is hyperventilation. Hyperventilation is when you breathe faster than the usual and normal. Severe hyperventilation can lead to unconsciousness, it narrows the blood vessels that supply blood to the brain because of low carbon dioxide
This is so rare, it happens occasionally for some people panicked response for fear, stress or a phiobia. For some this condition occurs when emotional states such as depression, anxiety or anger. Frequent happening of this is known hyperventilation syndrome.
