Hyperventilation is a condition that occurs when you begin to breathe very quickly. There are a number of things that can cause a person to hyperventilate. It occurs as a result of an imbalance in the amount of oxygen and carbon dioxide entering and exiting your body. With hyperventilation, there is a decrease in carbon dioxide which is caused by exhaling more than inhaling. There are millions of people in the United States who experience hyperventilation every day.